diff --git a/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduCalculatedProcessorField/lduCalculatedProcessorField.C b/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduCalculatedProcessorField/lduCalculatedProcessorField.C
index d60692571d..0fb082115b 100644
--- a/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduCalculatedProcessorField/lduCalculatedProcessorField.C
+++ b/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduCalculatedProcessorField/lduCalculatedProcessorField.C
@@ -58,12 +58,25 @@ Foam::lduCalculatedProcessorField<Type>::lduCalculatedProcessorField
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
 template<class Type>
-bool Foam::lduCalculatedProcessorField<Type>::ready() const
+bool Foam::lduCalculatedProcessorField<Type>::all_ready() const
 {
     return UPstream::finishedRequestPair(recvRequest_, sendRequest_);
 }
 
 
+template<class Type>
+bool Foam::lduCalculatedProcessorField<Type>::ready() const
+{
+    const bool ok = UPstream::finishedRequest(recvRequest_);
+    if (ok)
+    {
+        recvRequest_ = -1;
+        if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
+    }
+    return ok;
+}
+
+
 template<class Type>
 void Foam::lduCalculatedProcessorField<Type>::initInterfaceMatrixUpdate
 (
@@ -77,10 +90,11 @@ void Foam::lduCalculatedProcessorField<Type>::initInterfaceMatrixUpdate
     const Pstream::commsTypes commsType
 ) const
 {
-    if (!this->ready())
+    if (!this->all_ready())
     {
         FatalErrorInFunction
-            << "Outstanding request."
+            << "Outstanding request(s) on interface "
+            //<< procInterface_.name()
             << abort(FatalError);
     }
 
@@ -167,12 +181,12 @@ void Foam::lduCalculatedProcessorField<Type>::updateInterfaceMatrix
         return;
     }
 
-    // Require receive data. Update the send request state.
-    // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
-
-    UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
-    if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
-
+    {
+        // Require receive data.
+        // Only update the send request state.
+        UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
+        if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
+    }
 
     // Consume straight from receive buffer. Note use of our own
     // helper to avoid using fvPatch addressing
diff --git a/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduCalculatedProcessorField/lduCalculatedProcessorField.H b/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduCalculatedProcessorField/lduCalculatedProcessorField.H
index bb2cba44e4..c9af9ec11d 100644
--- a/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduCalculatedProcessorField/lduCalculatedProcessorField.H
+++ b/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduCalculatedProcessorField/lduCalculatedProcessorField.H
@@ -103,6 +103,9 @@ protected:
             const solveScalarField& vals
         ) const;
 
+        //- Receive and send requests have both completed
+        virtual bool all_ready() const;
+
 
 public:
 
@@ -112,14 +115,13 @@ public:
 
     // Constructors
 
-        //- Construct from patch and internal field
-        lduCalculatedProcessorField
+        //- Construct from ldu interface
+        explicit lduCalculatedProcessorField
         (
             const lduInterface& interface
-            //const Field<Type>&
         );
 
-        //- Construct as copy
+        //- Copy construct
         lduCalculatedProcessorField
         (
             const lduCalculatedProcessorField<Type>&
@@ -132,48 +134,9 @@ public:
 
     // Member Functions
 
-    // Access
-
-        //- Return communicator used for comms
-        virtual label comm() const
-        {
-            return procInterface_.comm();
-        }
-
-        //- Return processor number
-        virtual int myProcNo() const
-        {
-            return procInterface_.myProcNo();
-        }
-
-        //- Return neighbour processor number
-        virtual int neighbProcNo() const
-        {
-            return procInterface_.myProcNo();
-        }
-
-        //- Is the transform required
-        virtual bool doTransform() const
-        {
-            return false;
-        }
-
-        //- Return face transformation tensor
-        virtual const tensorField& forwardT() const
-        {
-            return procInterface_.forwardT();
-        }
-
-        //- Return rank of component for transform
-        virtual int rank() const
-        {
-            return pTraits<Type>::rank;
-        }
-
-
     // Evaluation
 
-        //- Is all data available
+        //- Are all (receive) data available?
         virtual bool ready() const;
 
         //- Initialise neighbour matrix update
@@ -231,6 +194,45 @@ public:
         {
             NotImplemented;
         }
+
+
+    // Processor coupled interface functions
+
+        //- Return communicator used for communication
+        virtual label comm() const
+        {
+            return procInterface_.comm();
+        }
+
+        //- Return processor number
+        virtual int myProcNo() const
+        {
+            return procInterface_.myProcNo();
+        }
+
+        //- Return neighbour processor number
+        virtual int neighbProcNo() const
+        {
+            return procInterface_.myProcNo();
+        }
+
+        //- Is the transform required
+        virtual bool doTransform() const
+        {
+            return false;
+        }
+
+        //- Return face transformation tensor
+        virtual const tensorField& forwardT() const
+        {
+            return procInterface_.forwardT();
+        }
+
+        //- Return rank of component for transform
+        virtual int rank() const
+        {
+            return pTraits<Type>::rank;
+        }
 };
 
 
diff --git a/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduPrimitiveProcessorInterface.C b/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduPrimitiveProcessorInterface.C
index 48074e2e3e..3f91831e90 100644
--- a/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduPrimitiveProcessorInterface.C
+++ b/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduPrimitiveProcessorInterface.C
@@ -136,4 +136,5 @@ Foam::lduPrimitiveProcessorInterface::internalFieldTransfer
     return processorLduInterface::receive<label>(commsType, faceCells_.size());
 }
 
+
 // ************************************************************************* //
diff --git a/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduPrimitiveProcessorInterface.H b/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduPrimitiveProcessorInterface.H
index 7314557de6..57063c1f2d 100644
--- a/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduPrimitiveProcessorInterface.H
+++ b/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduPrimitiveProcessorInterface.H
@@ -58,6 +58,7 @@ class lduPrimitiveProcessorInterface
 {
     // Private Data
 
+        //- Addressing
         const labelList faceCells_;
 
         //- My processor rank in communicator
@@ -76,19 +77,18 @@ class lduPrimitiveProcessorInterface
         const label comm_;
 
 
-    // Private Member Functions
-
-
-        //- No copy assignment
-        void operator=(const lduPrimitiveProcessorInterface&) = delete;
-
-
 public:
 
     //- Runtime type information
     TypeNameNoDebug("processorInterface");
 
 
+    // Generated Methods
+
+        //- No copy assignment
+        void operator=(const lduPrimitiveProcessorInterface&) = delete;
+
+
     // Constructors
 
         //- Construct from components
@@ -164,46 +164,46 @@ public:
             ) const;
 
 
-        // Processor interface functions
+    // Processor interface functions
 
-            //- Return communicator used for sending
-            virtual label comm() const
-            {
-                return comm_;
-            }
+        //- Return communicator used for sending
+        virtual label comm() const
+        {
+            return comm_;
+        }
 
-            //- Return processor number (rank in communicator)
-            virtual int myProcNo() const
-            {
-                return myProcNo_;
-            }
+        //- Return processor number (rank in communicator)
+        virtual int myProcNo() const
+        {
+            return myProcNo_;
+        }
 
-            //- Return neighbour processor number (rank in communicator)
-            virtual int neighbProcNo() const
-            {
-                return neighbProcNo_;
-            }
+        //- Return neighbour processor number (rank in communicator)
+        virtual int neighbProcNo() const
+        {
+            return neighbProcNo_;
+        }
 
-            //- Return face transformation tensor
-            virtual const tensorField& forwardT() const
-            {
-                return forwardT_;
-            }
+        //- Return face transformation tensor
+        virtual const tensorField& forwardT() const
+        {
+            return forwardT_;
+        }
 
-            //- Return message tag used for sending
-            virtual int tag() const
-            {
-                return tag_;
-            }
+        //- Return message tag used for sending
+        virtual int tag() const
+        {
+            return tag_;
+        }
 
 
-        // Edit
+    // Edit
 
-            //- Return message tag used for sending
-            int& tag()
-            {
-                return tag_;
-            }
+        //- Message tag used for sending (modifiable)
+        int& tag()
+        {
+            return tag_;
+        }
 };
 
 
diff --git a/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterfaceFields/lduInterfaceField/lduInterfaceField.H b/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterfaceFields/lduInterfaceField/lduInterfaceField.H
index f61e43e1d7..3eac6cb2d6 100644
--- a/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterfaceFields/lduInterfaceField/lduInterfaceField.H
+++ b/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterfaceFields/lduInterfaceField/lduInterfaceField.H
@@ -40,9 +40,9 @@ SourceFiles
 #define Foam_lduInterfaceField_H
 
 #include "lduInterface.H"
+#include "lduAddressing.H"
 #include "primitiveFieldsFwd.H"
 #include "Pstream.H"
-#include "lduAddressing.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
@@ -100,43 +100,44 @@ public:
 
     // Member Functions
 
-        // Access
+        //- Return the interface
+        const lduInterface& interface() const noexcept
+        {
+            return interface_;
+        }
 
-            //- Return the interface
-            const lduInterface& interface() const noexcept
-            {
-                return interface_;
-            }
+        //- Return the interface type
+        virtual const word& interfaceFieldType() const
+        {
+            return type();
+        }
 
-            //- Return the interface type
-            virtual const word& interfaceFieldType() const
-            {
-                return type();
-            }
+
+    // Coupled Interface
+
+        //- Are all (receive) data available?
+        virtual bool ready() const
+        {
+            return true;
+        }
+
+        //- Whether matrix has been updated
+        bool updatedMatrix() const noexcept
+        {
+            return updatedMatrix_;
+        }
+
+        //- Set matrix as update-to-date, return the previous value
+        bool updatedMatrix(bool flag) const noexcept
+        {
+            bool old(updatedMatrix_);
+            updatedMatrix_ = flag;
+            return old;
+        }
 
 
         // Coupled interface matrix update
 
-            //- Whether matrix has been updated
-            bool updatedMatrix() const noexcept
-            {
-                return updatedMatrix_;
-            }
-
-            //- Set matrix as update-to-date, return the previous value
-            bool updatedMatrix(bool flag) const noexcept
-            {
-                bool old(updatedMatrix_);
-                updatedMatrix_ = flag;
-                return old;
-            }
-
-            //- Is all data available
-            virtual bool ready() const
-            {
-                return true;
-            }
-
             //- Initialise neighbour matrix update.
             //- Add/subtract coupled contributions to matrix
             virtual void initInterfaceMatrixUpdate
diff --git a/src/finiteArea/fields/faPatchFields/constraint/processor/processorFaPatchField.C b/src/finiteArea/fields/faPatchFields/constraint/processor/processorFaPatchField.C
index 70935bcf79..fe31f3761c 100644
--- a/src/finiteArea/fields/faPatchFields/constraint/processor/processorFaPatchField.C
+++ b/src/finiteArea/fields/faPatchFields/constraint/processor/processorFaPatchField.C
@@ -84,10 +84,10 @@ Foam::processorFaPatchField<Type>::processorFaPatchField
             << " in file " << this->internalField().objectPath()
             << exit(FatalError);
     }
-    if (debug && !ptf.ready())
+    if (debug && !ptf.all_ready())
     {
         FatalErrorInFunction
-            << "On patch " << procPatch_.name() << " outstanding request."
+            << "Outstanding request(s) on patch " << procPatch_.name()
             << abort(FatalError);
     }
 }
@@ -141,10 +141,10 @@ Foam::processorFaPatchField<Type>::processorFaPatchField
     scalarSendBuf_(std::move(ptf.scalarSendBuf_)),
     scalarRecvBuf_(std::move(ptf.scalarRecvBuf_))
 {
-    if (debug && !ptf.ready())
+    if (debug && !ptf.all_ready())
     {
         FatalErrorInFunction
-            << "On patch " << procPatch_.name() << " outstanding request."
+            << "Outstanding request(s) on patch " << procPatch_.name()
             << abort(FatalError);
     }
 }
@@ -162,10 +162,10 @@ Foam::processorFaPatchField<Type>::processorFaPatchField
     sendRequest_(-1),
     recvRequest_(-1)
 {
-    if (debug && !ptf.ready())
+    if (debug && !ptf.all_ready())
     {
         FatalErrorInFunction
-            << "On patch " << procPatch_.name() << " outstanding request."
+            << "Outstanding request(s) on patch " << procPatch_.name()
             << abort(FatalError);
     }
 }
@@ -174,12 +174,25 @@ Foam::processorFaPatchField<Type>::processorFaPatchField
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
 template<class Type>
-bool Foam::processorFaPatchField<Type>::ready() const
+bool Foam::processorFaPatchField<Type>::all_ready() const
 {
     return UPstream::finishedRequestPair(recvRequest_, sendRequest_);
 }
 
 
+template<class Type>
+bool Foam::processorFaPatchField<Type>::ready() const
+{
+    const bool ok = UPstream::finishedRequest(recvRequest_);
+    if (ok)
+    {
+        recvRequest_ = -1;
+        if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
+    }
+    return ok;
+}
+
+
 template<class Type>
 Foam::tmp<Foam::Field<Type>>
 Foam::processorFaPatchField<Type>::patchNeighbourField() const
@@ -187,8 +200,7 @@ Foam::processorFaPatchField<Type>::patchNeighbourField() const
     if (debug && !this->ready())
     {
         FatalErrorInFunction
-            << "On patch " << procPatch_.name()
-            << " outstanding request."
+            << "Outstanding request on patch " << procPatch_.name()
             << abort(FatalError);
     }
     return *this;
@@ -259,9 +271,8 @@ void Foam::processorFaPatchField<Type>::evaluate
         {
             // Fast path. Received into *this
 
-            // Require receive data. Update the send request state.
-            // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
-
+            // Require receive data.
+            // Only update the send request state.
             UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
             if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
         }
@@ -303,11 +314,10 @@ void Foam::processorFaPatchField<Type>::initInterfaceMatrixUpdate
     if (commsType == UPstream::commsTypes::nonBlocking)
     {
         // Fast path.
-        if (debug && !this->ready())
+        if (debug && !this->all_ready())
         {
             FatalErrorInFunction
-                << "On patch " << procPatch_.name()
-                << " outstanding request."
+                << "Outstanding request(s) on patch " << procPatch_.name()
                 << abort(FatalError);
         }
 
@@ -368,9 +378,8 @@ void Foam::processorFaPatchField<Type>::updateInterfaceMatrix
     {
         // Fast path: consume straight from receive buffer
 
-        // Require receive data. Update the send request state.
-        // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
-
+        // Require receive data.
+        // Only update the send request state.
         UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
         if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
     }
@@ -411,11 +420,10 @@ void Foam::processorFaPatchField<Type>::initInterfaceMatrixUpdate
     if (commsType == UPstream::commsTypes::nonBlocking)
     {
         // Fast path.
-        if (debug && !this->ready())
+        if (debug && !this->all_ready())
         {
             FatalErrorInFunction
-                << "On patch " << procPatch_.name()
-                << " outstanding request."
+                << "Outstanding request(s) on patch " << procPatch_.name()
                 << abort(FatalError);
         }
 
@@ -475,9 +483,8 @@ void Foam::processorFaPatchField<Type>::updateInterfaceMatrix
     {
         // Fast path: consume straight from receive buffer
 
-        // Require receive data. Update the send request state.
-        // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
-
+        // Require receive data.
+        // Only update the send request state.
         UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
         if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
     }
diff --git a/src/finiteArea/fields/faPatchFields/constraint/processor/processorFaPatchField.H b/src/finiteArea/fields/faPatchFields/constraint/processor/processorFaPatchField.H
index 9d903ffb67..960b70a224 100644
--- a/src/finiteArea/fields/faPatchFields/constraint/processor/processorFaPatchField.H
+++ b/src/finiteArea/fields/faPatchFields/constraint/processor/processorFaPatchField.H
@@ -88,6 +88,12 @@ class processorFaPatchField
             mutable solveScalarField scalarRecvBuf_;
 
 
+    // Private Member Functions
+
+        //- Receive and send requests have both completed
+        virtual bool all_ready() const;
+
+
 public:
 
     //- Runtime type information
@@ -164,33 +170,30 @@ public:
     ~processorFaPatchField() = default;
 
 
-    // Member functions
+    // Member Functions
 
-        // Access
+    // Coupling
 
-            //- Return true if running parallel
-            virtual bool coupled() const
-            {
-                return Pstream::parRun();
-            }
+        //- The patch field is coupled if running in parallel
+        virtual bool coupled() const { return UPstream::parRun(); }
 
-            //- Return neighbour field given internal field
-            tmp<Field<Type>> patchNeighbourField() const;
+        //- Are all (receive) data available?
+        virtual bool ready() const;
+
+        //- Return neighbour field given internal field
+        tmp<Field<Type>> patchNeighbourField() const;
 
 
-        // Evaluation functions
+    // Evaluation
 
-            //- Initialise the evaluation of the patch field
-            virtual void initEvaluate(const Pstream::commsTypes commsType);
+        //- Initialise the evaluation of the patch field
+        virtual void initEvaluate(const Pstream::commsTypes commsType);
 
-            //- Evaluate the patch field
-            virtual void evaluate(const Pstream::commsTypes commsType);
+        //- Evaluate the patch field
+        virtual void evaluate(const Pstream::commsTypes commsType);
 
-            //- Return patch-normal gradient
-            virtual tmp<Field<Type>> snGrad() const;
-
-            //- Is all data available
-            virtual bool ready() const;
+        //- Return patch-normal gradient
+        virtual tmp<Field<Type>> snGrad() const;
 
 
         // Coupled interface functionality
@@ -245,43 +248,44 @@ public:
                 const Pstream::commsTypes commsType
             ) const;
 
-        //- Processor coupled interface functions
 
-            //- Return communicator used for comms
-            virtual label comm() const
-            {
-                return UPstream::worldComm;
-            }
+    // Processor coupled interface functions
 
-            //- Return processor number
-            virtual int myProcNo() const
-            {
-                return procPatch_.myProcNo();
-            }
+        //- Return communicator used for communication
+        virtual label comm() const
+        {
+            return procPatch_.comm();
+        }
 
-            //- Return neighbour processor number
-            virtual int neighbProcNo() const
-            {
-                return procPatch_.neighbProcNo();
-            }
+        //- Return processor number
+        virtual int myProcNo() const
+        {
+            return procPatch_.myProcNo();
+        }
 
-            //- Does the patch field perform the transformation
-            virtual bool doTransform() const
-            {
-                return (pTraits<Type>::rank && !procPatch_.parallel());
-            }
+        //- Return neighbour processor number
+        virtual int neighbProcNo() const
+        {
+            return procPatch_.neighbProcNo();
+        }
 
-            //- Return face transformation tensor
-            virtual const tensorField& forwardT() const
-            {
-                return procPatch_.forwardT();
-            }
+        //- Does the patch field perform the transformation
+        virtual bool doTransform() const
+        {
+            return (pTraits<Type>::rank && !procPatch_.parallel());
+        }
 
-            //- Return rank of component for transform
-            virtual int rank() const
-            {
-                return pTraits<Type>::rank;
-            }
+        //- Return face transformation tensor
+        virtual const tensorField& forwardT() const
+        {
+            return procPatch_.forwardT();
+        }
+
+        //- Return rank of component for transform
+        virtual int rank() const
+        {
+            return pTraits<Type>::rank;
+        }
 };
 
 
diff --git a/src/finiteVolume/fields/fvPatchFields/constraint/calculatedProcessor/calculatedProcessorFvPatchField.C b/src/finiteVolume/fields/fvPatchFields/constraint/calculatedProcessor/calculatedProcessorFvPatchField.C
index 25e6ee5a23..6b346a2f9d 100644
--- a/src/finiteVolume/fields/fvPatchFields/constraint/calculatedProcessor/calculatedProcessorFvPatchField.C
+++ b/src/finiteVolume/fields/fvPatchFields/constraint/calculatedProcessor/calculatedProcessorFvPatchField.C
@@ -74,12 +74,25 @@ Foam::calculatedProcessorFvPatchField<Type>::calculatedProcessorFvPatchField
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
 template<class Type>
-bool Foam::calculatedProcessorFvPatchField<Type>::ready() const
+bool Foam::calculatedProcessorFvPatchField<Type>::all_ready() const
 {
     return UPstream::finishedRequestPair(recvRequest_, sendRequest_);
 }
 
 
+template<class Type>
+bool Foam::calculatedProcessorFvPatchField<Type>::ready() const
+{
+    const bool ok = UPstream::finishedRequest(recvRequest_);
+    if (ok)
+    {
+        recvRequest_ = -1;
+        if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
+    }
+    return ok;
+}
+
+
 template<class Type>
 Foam::tmp<Foam::Field<Type>>
 Foam::calculatedProcessorFvPatchField<Type>::patchNeighbourField() const
@@ -87,10 +100,10 @@ Foam::calculatedProcessorFvPatchField<Type>::patchNeighbourField() const
     if (!this->ready())
     {
         FatalErrorInFunction
-            << "On patch of size " << procInterface_.faceCells().size()
+            << "Outstanding request on patch of size "
+            << procInterface_.faceCells().size()
             << " between proc " << procInterface_.myProcNo()
             << " and " << procInterface_.neighbProcNo()
-            << " outstanding request."
             << abort(FatalError);
     }
     return *this;
@@ -160,9 +173,8 @@ void Foam::calculatedProcessorFvPatchField<Type>::evaluate
 {
     if (UPstream::parRun())
     {
-        // Require receive data. Update the send request state.
-        // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
-
+        // Require receive data.
+        // Only update the send request state.
         UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
         if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
     }
@@ -182,11 +194,11 @@ void Foam::calculatedProcessorFvPatchField<Type>::initInterfaceMatrixUpdate
     const Pstream::commsTypes commsType
 ) const
 {
-    if (!this->ready())
+    if (!this->all_ready())
     {
         FatalErrorInFunction
-            << "On patch " //<< interface_.name()
-            << " outstanding request."
+            << "Outstanding request(s) on interface "
+            //<< interface_.name()
             << abort(FatalError);
     }
 
@@ -275,9 +287,8 @@ void Foam::calculatedProcessorFvPatchField<Type>::updateInterfaceMatrix
 
     if (UPstream::parRun())
     {
-        // Require receive data. Update the send request state.
-        // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
-
+        // Require receive data.
+        // Only update the send request state.
         UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
         if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
     }
diff --git a/src/finiteVolume/fields/fvPatchFields/constraint/calculatedProcessor/calculatedProcessorFvPatchField.H b/src/finiteVolume/fields/fvPatchFields/constraint/calculatedProcessor/calculatedProcessorFvPatchField.H
index 7367148a71..ef6807119e 100644
--- a/src/finiteVolume/fields/fvPatchFields/constraint/calculatedProcessor/calculatedProcessorFvPatchField.H
+++ b/src/finiteVolume/fields/fvPatchFields/constraint/calculatedProcessor/calculatedProcessorFvPatchField.H
@@ -68,7 +68,7 @@ class calculatedProcessorFvPatchField
 {
 protected:
 
-    // Protected data
+    // Protected Data
 
          //- Local reference cast into the interface
          const lduPrimitiveProcessorInterface& procInterface_;
@@ -106,6 +106,10 @@ protected:
         ) const;
 
 
+        //- Receive and send requests have both completed
+        virtual bool all_ready() const;
+
+
 public:
 
     //- Runtime type information
@@ -161,73 +165,30 @@ public:
     virtual ~calculatedProcessorFvPatchField() = default;
 
 
-    // Member functions
+    // Member Functions
 
-        // processorLduInterfaceField implementation
+    // Coupling
 
-            //- Return communicator used for comms
-            virtual label comm() const
-            {
-                return procInterface_.comm();
-            }
+        //- The patch field is coupled if running in parallel
+        virtual bool coupled() const { return UPstream::parRun(); }
 
-            //- Return processor number
-            virtual int myProcNo() const
-            {
-                return procInterface_.myProcNo();
-            }
+        //- Are all (receive) data available?
+        virtual bool ready() const;
+
+        //- Return neighbour field of internal field
+        virtual tmp<Field<Type>> patchNeighbourField() const;
 
 
-            //- Return neighbour processor number
-            virtual int neighbProcNo() const
-            {
-                return procInterface_.myProcNo();
-            }
+    // Evaluation
 
-            //- Is the transform required
-            virtual bool doTransform() const
-            {
-                return false;
-            }
+        //- Initialise the evaluation of the patch field
+        virtual void initEvaluate(const Pstream::commsTypes commsType);
 
-            //- Return face transformation tensor
-            virtual const tensorField& forwardT() const
-            {
-                return procInterface_.forwardT();
-            }
-
-            //- Return rank of component for transform
-            virtual int rank() const
-            {
-                return pTraits<Type>::rank;
-            }
+        //- Evaluate the patch field
+        virtual void evaluate(const Pstream::commsTypes commsType);
 
 
-        // Access
-
-            //- Return true if this patch field is coupled.
-            //  Our field supplies coefficients to the fvMatrix so
-            //  should behave as a processorFvPatchField (in
-            //  addBoundarySource it should not add to the source)
-            virtual bool coupled() const
-            {
-                return Pstream::parRun();
-            }
-
-            //- Return neighbour field of internal field
-            virtual tmp<Field<Type>> patchNeighbourField() const;
-
-
-        // Evaluation functions
-
-            //- Is all data available
-            virtual bool ready() const;
-
-            //- Initialise the evaluation of the patch field
-            virtual void initEvaluate(const Pstream::commsTypes commsType);
-
-            //- Evaluate the patch field
-            virtual void evaluate(const Pstream::commsTypes commsType);
+        // Coupled interface functionality
 
             //- Initialise neighbour matrix update
             virtual void initInterfaceMatrixUpdate
@@ -285,8 +246,44 @@ public:
                 NotImplemented;
             }
 
-        //- Write
-        // virtual void write(Ostream& os) const;
+
+    // Processor coupled interface functions
+
+        //- Return communicator used for communication
+        virtual label comm() const
+        {
+            return procInterface_.comm();
+        }
+
+        //- Return processor number
+        virtual int myProcNo() const
+        {
+            return procInterface_.myProcNo();
+        }
+
+        //- Return neighbour processor number
+        virtual int neighbProcNo() const
+        {
+            return procInterface_.myProcNo();
+        }
+
+        //- Is the transform required
+        virtual bool doTransform() const
+        {
+            return false;
+        }
+
+        //- Return face transformation tensor
+        virtual const tensorField& forwardT() const
+        {
+            return procInterface_.forwardT();
+        }
+
+        //- Return rank of component for transform
+        virtual int rank() const
+        {
+            return pTraits<Type>::rank;
+        }
 };
 
 
diff --git a/src/finiteVolume/fields/fvPatchFields/constraint/processor/processorFvPatchField.C b/src/finiteVolume/fields/fvPatchFields/constraint/processor/processorFvPatchField.C
index 3fdec71d96..19da597026 100644
--- a/src/finiteVolume/fields/fvPatchFields/constraint/processor/processorFvPatchField.C
+++ b/src/finiteVolume/fields/fvPatchFields/constraint/processor/processorFvPatchField.C
@@ -118,10 +118,10 @@ Foam::processorFvPatchField<Type>::processorFvPatchField
             << " in file " << this->internalField().objectPath()
             << exit(FatalError);
     }
-    if (debug && !ptf.ready())
+    if (debug && !ptf.all_ready())
     {
         FatalErrorInFunction
-            << "On patch " << procPatch_.name() << " outstanding request."
+            << "Outstanding request(s) on patch " << procPatch_.name()
             << abort(FatalError);
     }
 }
@@ -143,10 +143,10 @@ Foam::processorFvPatchField<Type>::processorFvPatchField
     scalarSendBuf_(std::move(ptf.scalarSendBuf_)),
     scalarRecvBuf_(std::move(ptf.scalarRecvBuf_))
 {
-    if (debug && !ptf.ready())
+    if (debug && !ptf.all_ready())
     {
         FatalErrorInFunction
-            << "On patch " << procPatch_.name() << " outstanding request."
+            << "Outstanding request(s) on patch " << procPatch_.name()
             << abort(FatalError);
     }
 }
@@ -164,10 +164,10 @@ Foam::processorFvPatchField<Type>::processorFvPatchField
     sendRequest_(-1),
     recvRequest_(-1)
 {
-    if (debug && !ptf.ready())
+    if (debug && !ptf.all_ready())
     {
         FatalErrorInFunction
-            << "On patch " << procPatch_.name() << " outstanding request."
+            << "Outstanding request(s) on patch " << procPatch_.name()
             << abort(FatalError);
     }
 }
@@ -176,12 +176,25 @@ Foam::processorFvPatchField<Type>::processorFvPatchField
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
 template<class Type>
-bool Foam::processorFvPatchField<Type>::ready() const
+bool Foam::processorFvPatchField<Type>::all_ready() const
 {
     return UPstream::finishedRequestPair(recvRequest_, sendRequest_);
 }
 
 
+template<class Type>
+bool Foam::processorFvPatchField<Type>::ready() const
+{
+    const bool ok = UPstream::finishedRequest(recvRequest_);
+    if (ok)
+    {
+        recvRequest_ = -1;
+        if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
+    }
+    return ok;
+}
+
+
 template<class Type>
 Foam::tmp<Foam::Field<Type>>
 Foam::processorFvPatchField<Type>::patchNeighbourField() const
@@ -189,8 +202,7 @@ Foam::processorFvPatchField<Type>::patchNeighbourField() const
     if (debug && !this->ready())
     {
         FatalErrorInFunction
-            << "On patch " << procPatch_.name()
-            << " outstanding request."
+            << "Outstanding request on patch " << procPatch_.name()
             << abort(FatalError);
     }
     return *this;
@@ -209,7 +221,7 @@ void Foam::processorFvPatchField<Type>::initEvaluate
 
         if
         (
-            commsType == Pstream::commsTypes::nonBlocking
+            commsType == UPstream::commsTypes::nonBlocking
          && (std::is_integral<Type>::value || !UPstream::floatTransfer)
         )
         {
@@ -263,15 +275,14 @@ void Foam::processorFvPatchField<Type>::evaluate
     {
         if
         (
-            commsType == Pstream::commsTypes::nonBlocking
+            commsType == UPstream::commsTypes::nonBlocking
          && (std::is_integral<Type>::value || !UPstream::floatTransfer)
         )
         {
             // Fast path: received into *this
 
-            // Require receive data. Update the send request state.
-            // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
-
+            // Require receive data.
+            // Only update the send request state.
             UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
             if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
         }
@@ -324,16 +335,15 @@ void Foam::processorFvPatchField<Type>::initInterfaceMatrixUpdate
 
     if
     (
-        commsType == Pstream::commsTypes::nonBlocking
+        commsType == UPstream::commsTypes::nonBlocking
      && !UPstream::floatTransfer
     )
     {
         // Fast path.
-        if (debug && !this->ready())
+        if (debug && !this->all_ready())
         {
             FatalErrorInFunction
-                << "On patch " << procPatch_.name()
-                << " outstanding request."
+                << "Outstanding request(s) on patch " << procPatch_.name()
                 << abort(FatalError);
         }
 
@@ -392,15 +402,14 @@ void Foam::processorFvPatchField<Type>::updateInterfaceMatrix
 
     if
     (
-        commsType == Pstream::commsTypes::nonBlocking
+        commsType == UPstream::commsTypes::nonBlocking
      && !UPstream::floatTransfer
     )
     {
         // Fast path: consume straight from receive buffer
 
-        // Require receive data. Update the send request state.
-        // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
-
+        // Require receive data.
+        // Only update the send request state.
         UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
         if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
     }
@@ -447,16 +456,15 @@ void Foam::processorFvPatchField<Type>::initInterfaceMatrixUpdate
 
     if
     (
-        commsType == Pstream::commsTypes::nonBlocking
+        commsType == UPstream::commsTypes::nonBlocking
      && (std::is_integral<Type>::value || !UPstream::floatTransfer)
     )
     {
         // Fast path.
-        if (debug && !this->ready())
+        if (debug && !this->all_ready())
         {
             FatalErrorInFunction
-                << "On patch " << procPatch_.name()
-                << " outstanding request."
+                << "Outstanding request(s) on patch " << procPatch_.name()
                 << abort(FatalError);
         }
 
@@ -514,15 +522,14 @@ void Foam::processorFvPatchField<Type>::updateInterfaceMatrix
 
     if
     (
-        commsType == Pstream::commsTypes::nonBlocking
+        commsType == UPstream::commsTypes::nonBlocking
      && (std::is_integral<Type>::value || !UPstream::floatTransfer)
     )
     {
         // Fast path: consume straight from receive buffer
 
-        // Require receive data. Update the send request state.
-        // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
-
+        // Require receive data.
+        // Only update the send request state.
         UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
         if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
     }
diff --git a/src/finiteVolume/fields/fvPatchFields/constraint/processor/processorFvPatchField.H b/src/finiteVolume/fields/fvPatchFields/constraint/processor/processorFvPatchField.H
index 48e2f092ba..7c83568c3d 100644
--- a/src/finiteVolume/fields/fvPatchFields/constraint/processor/processorFvPatchField.H
+++ b/src/finiteVolume/fields/fvPatchFields/constraint/processor/processorFvPatchField.H
@@ -96,6 +96,12 @@ class processorFvPatchField
             mutable solveScalarField scalarRecvBuf_;
 
 
+    // Private Member Functions
+
+        //- Receive and send requests have both completed
+        virtual bool all_ready() const;
+
+
 public:
 
     //- Runtime type information
@@ -174,34 +180,34 @@ public:
 
     // Member Functions
 
-        // Access
+    // Coupling
 
-            //- Return true if running parallel
-            virtual bool coupled() const
-            {
-                return Pstream::parRun();
-            }
+        //- The patch field is coupled if running in parallel
+        virtual bool coupled() const { return UPstream::parRun(); }
 
-            //- Return neighbour field given internal field
-            virtual tmp<Field<Type>> patchNeighbourField() const;
+        //- Are all (receive) data available?
+        virtual bool ready() const;
+
+        //- Return neighbour field given internal field
+        virtual tmp<Field<Type>> patchNeighbourField() const;
 
 
-        // Evaluation functions
+    // Evaluation
 
-            //- Initialise the evaluation of the patch field
-            virtual void initEvaluate(const Pstream::commsTypes commsType);
+        //- Initialise the evaluation of the patch field
+        virtual void initEvaluate(const Pstream::commsTypes commsType);
 
-            //- Evaluate the patch field
-            virtual void evaluate(const Pstream::commsTypes commsType);
+        //- Evaluate the patch field
+        virtual void evaluate(const Pstream::commsTypes commsType);
 
-            //- Return patch-normal gradient
-            virtual tmp<Field<Type>> snGrad
-            (
-                const scalarField& deltaCoeffs
-            ) const;
+        //- Return patch-normal gradient
+        virtual tmp<Field<Type>> snGrad
+        (
+            const scalarField& deltaCoeffs
+        ) const;
 
-            //- Is all data available
-            virtual bool ready() const;
+
+        // Coupled interface functionality
 
             //- Initialise neighbour matrix update
             virtual void initInterfaceMatrixUpdate
@@ -254,43 +260,43 @@ public:
             ) const;
 
 
-        //- Processor coupled interface functions
+    // Processor coupled interface functions
 
-            //- Return communicator used for comms
-            virtual label comm() const
-            {
-                return procPatch_.comm();
-            }
+        //- Return communicator used for communication
+        virtual label comm() const
+        {
+            return procPatch_.comm();
+        }
 
-            //- Return processor number
-            virtual int myProcNo() const
-            {
-                return procPatch_.myProcNo();
-            }
+        //- Return processor number
+        virtual int myProcNo() const
+        {
+            return procPatch_.myProcNo();
+        }
 
-            //- Return neighbour processor number
-            virtual int neighbProcNo() const
-            {
-                return procPatch_.neighbProcNo();
-            }
+        //- Return neighbour processor number
+        virtual int neighbProcNo() const
+        {
+            return procPatch_.neighbProcNo();
+        }
 
-            //- Does the patch field perform the transformation
-            virtual bool doTransform() const
-            {
-                return (pTraits<Type>::rank && !procPatch_.parallel());
-            }
+        //- Does the patch field perform the transformation
+        virtual bool doTransform() const
+        {
+            return (pTraits<Type>::rank && !procPatch_.parallel());
+        }
 
-            //- Return face transformation tensor
-            virtual const tensorField& forwardT() const
-            {
-                return procPatch_.forwardT();
-            }
+        //- Return face transformation tensor
+        virtual const tensorField& forwardT() const
+        {
+            return procPatch_.forwardT();
+        }
 
-            //- Return rank of component for transform
-            virtual int rank() const
-            {
-                return pTraits<Type>::rank;
-            }
+        //- Return rank of component for transform
+        virtual int rank() const
+        {
+            return pTraits<Type>::rank;
+        }
 };