diff --git a/src/lagrangian/cfdemParticle/cfdemCloud/cfdemCloud.C b/src/lagrangian/cfdemParticle/cfdemCloud/cfdemCloud.C
index 5702c2f5..bb205cc4 100644
--- a/src/lagrangian/cfdemParticle/cfdemCloud/cfdemCloud.C
+++ b/src/lagrangian/cfdemParticle/cfdemCloud/cfdemCloud.C
@@ -673,13 +673,7 @@ bool cfdemCloud::evolve
         int old_precision = Info().precision(10);
         Info << "\n timeStepFraction() = " << timeStepFrac << endl;
         Info().precision(old_precision);
-        if(timeStepFrac > 1.0000001)
-        {
-   //         FatalError << "cfdemCloud::dataExchangeM().timeStepFraction()>1: Do not do this, since dangerous. This might be due to the fact that you used a adjustable CFD time step. Please use a fixed CFD time step." << abort(FatalError);
-              old_precision = Warning().precision(10);
-              Warning << "cfdemCloud::dataExchangeM().timeStepFraction() = " << timeStepFrac << endl;
-              Warning().precision(old_precision);
-        }
+
         clockM().start(24,"interpolateEulerFields");
 
         // update voidFractionField
diff --git a/src/lagrangian/cfdemParticle/subModels/dataExchangeModel/dataExchangeModel/dataExchangeModel.C b/src/lagrangian/cfdemParticle/subModels/dataExchangeModel/dataExchangeModel/dataExchangeModel.C
index 723db484..168f513c 100755
--- a/src/lagrangian/cfdemParticle/subModels/dataExchangeModel/dataExchangeModel/dataExchangeModel.C
+++ b/src/lagrangian/cfdemParticle/subModels/dataExchangeModel/dataExchangeModel/dataExchangeModel.C
@@ -209,7 +209,7 @@ bool dataExchangeModel::couple(int i)
 scalar dataExchangeModel::timeStepFraction() const
 {
     //return fraction between previous coupling TS and actual TS
-    return ( particleCloud_.mesh().time().value()-particleCloud_.mesh().time().startTime().value() - (couplingStep_-1) * couplingTime() ) / couplingTime();
+    return clamp( (particleCloud_.mesh().time().timeIndex() - timeIndexOffset_) * particleCloud_.mesh().time().deltaTValue() / couplingTime() - (couplingStep_ - 1) );
 }
 
 int dataExchangeModel::getNumberOfParticles() const
@@ -249,7 +249,8 @@ dataExchangeModel::dataExchangeModel
     maxNumberOfParticles_(0),
     couplingStep_(0),
     DEMts_(-1.),
-    couplingInterval_(readScalar(dict_.lookup("couplingInterval")))
+    couplingInterval_(readScalar(dict_.lookup("couplingInterval"))),
+    timeIndexOffset_(particleCloud_.mesh().time().timeIndex())
 {}
 
 // * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
diff --git a/src/lagrangian/cfdemParticle/subModels/dataExchangeModel/dataExchangeModel/dataExchangeModel.H b/src/lagrangian/cfdemParticle/subModels/dataExchangeModel/dataExchangeModel/dataExchangeModel.H
index e146b0ff..7d483325 100755
--- a/src/lagrangian/cfdemParticle/subModels/dataExchangeModel/dataExchangeModel/dataExchangeModel.H
+++ b/src/lagrangian/cfdemParticle/subModels/dataExchangeModel/dataExchangeModel/dataExchangeModel.H
@@ -68,8 +68,16 @@ protected:
 
         int couplingInterval_;
 
+        const label timeIndexOffset_;
+
     // Protected member functions
 
+        // note: C++17 has std::clamp
+        scalar clamp(scalar v, scalar lo=0.0, scalar hi=1.0) const
+        {
+            return ((v < lo) ? lo : (hi < v) ? hi : v);
+        }
+
 public:
 
     //- Runtime type information
@@ -198,26 +206,28 @@ public:
 
         inline void checkTSsize() const
         {
-            if (particleCloud_.mesh().time().deltaT().value() >  couplingInterval_ * DEMts_ + SMALL)
+            if (particleCloud_.mesh().time().deltaTValue() >  couplingInterval_ * DEMts_ + SMALL)
             {
-                Info << "particleCloud_.mesh().time().deltaT().value() = " << particleCloud_.mesh().time().deltaT().value() << endl;
+                Info << "particleCloud_.mesh().time().deltaTValue() = " << particleCloud_.mesh().time().deltaTValue() << endl;
                 Info << "couplingInterval_ = " << couplingInterval_ << endl;
                 Info << "DEMts_ = " << DEMts_ << endl;
                 FatalError << "\nError - CFD time-step bigger than coupling time (= DEM time step * coupling interval)!\n" << abort(FatalError);
             }
-            if (std::fabs((round(couplingTime()/particleCloud_.mesh().time().deltaT().value())*particleCloud_.mesh().time().deltaT().value())-couplingTime()) > SMALL)
+
+            if (std::fabs((round(couplingTime()/particleCloud_.mesh().time().deltaTValue()) * particleCloud_.mesh().time().deltaTValue()) - couplingTime()) > SMALL)
             {
-                Info << "particleCloud_.mesh().time().deltaT().value() = " << particleCloud_.mesh().time().deltaT().value() << endl;
+                Info << "particleCloud_.mesh().time().deltaTValue() = " << particleCloud_.mesh().time().deltaTValue() << endl;
                 Info << "couplingInterval_ = " << couplingInterval_ << endl;
                 Info << "DEMts_ = " << DEMts_ << endl;
                 Warning << "\nWarning - Coupling time (= DEM time step * coupling interval) is not a multiple of CFD time-step!\n" << endl;
             }
+
             if (!particleCloud_.allowCFDsubTimestep())
-                if (particleCloud_.mesh().time().deltaT().value() < couplingInterval_ * DEMts_ + SMALL)
+                if (particleCloud_.mesh().time().deltaTValue() < couplingInterval_ * DEMts_ + SMALL)
                     FatalError << "\nYour models require: CFD time-step = coupling interval (= DEM time step * coupling interval)! \n" << abort(FatalError);
 
             // warn if sub-TS
-            if (particleCloud_.mesh().time().deltaT().value() < couplingTime() - SMALL)
+            if (particleCloud_.mesh().time().deltaTValue() < couplingTime() - SMALL)
                 Warning << "You are using sub-time-steps (i.e. CFD TS < coupling time)! Check your settings properly." << endl;
         }
 
@@ -229,15 +239,10 @@ public:
 
         inline bool doCoupleNow() const
         {
-            if (particleCloud_.mesh().time().value()-particleCloud_.mesh().time().startTime().value()-SMALL
-                > couplingStep_*DEMts_*couplingInterval_)
-            {
-                return true;
-            }
-            else
-            {
-                return false;
-            }
+            return ( (particleCloud_.mesh().time().timeIndex() - timeIndexOffset_) * particleCloud_.mesh().time().deltaTValue() - SMALL
+                     >
+                     couplingStep_ * DEMts_ * couplingInterval_
+                   );
         }
 
         virtual int getNumberOfParticles() const;