diff --git a/src/functionObjects/field/fieldAverage/fieldAverageTemplates.C b/src/functionObjects/field/fieldAverage/fieldAverageTemplates.C
index 87da1e3cb1..0dbd553a49 100644
--- a/src/functionObjects/field/fieldAverage/fieldAverageTemplates.C
+++ b/src/functionObjects/field/fieldAverage/fieldAverageTemplates.C
@@ -210,11 +210,10 @@ void Foam::functionObjects::fieldAverage::calculateMeanFieldType
 
         if (faItems_[fieldi].iterBase())
         {
-            dt = 1.0;
+            dt = 1;
             Dt = scalar(totalIter_[fieldi]);
         }
 
-        scalar alpha = (Dt - dt)/Dt;
         scalar beta = dt/Dt;
 
         if (faItems_[fieldi].window() > 0)
@@ -223,12 +222,11 @@ void Foam::functionObjects::fieldAverage::calculateMeanFieldType
 
             if (Dt - dt >= w)
             {
-                alpha = (w - dt)/w;
                 beta = dt/w;
             }
         }
 
-        meanField = alpha*meanField + beta*baseField;
+        meanField = (1 - beta)*meanField + beta*baseField;
     }
 }
 
@@ -274,11 +272,10 @@ void Foam::functionObjects::fieldAverage::calculatePrime2MeanFieldType
 
         if (faItems_[fieldi].iterBase())
         {
-            dt = 1.0;
+            dt = 1;
             Dt = scalar(totalIter_[fieldi]);
         }
 
-        scalar alpha = (Dt - dt)/Dt;
         scalar beta = dt/Dt;
 
         if (faItems_[fieldi].window() > 0)
@@ -287,13 +284,12 @@ void Foam::functionObjects::fieldAverage::calculatePrime2MeanFieldType
 
             if (Dt - dt >= w)
             {
-                alpha = (w - dt)/w;
                 beta = dt/w;
             }
         }
 
         prime2MeanField =
-            alpha*prime2MeanField
+            (1 - beta)*prime2MeanField
           + beta*sqr(baseField)
           - sqr(meanField);
     }
@@ -313,11 +309,7 @@ void Foam::functionObjects::fieldAverage::calculatePrime2MeanFields() const
     {
         if (faItems_[i].prime2Mean())
         {
-            calculatePrime2MeanFieldType<VolFieldType1, VolFieldType2>
-            (
-                i
-            );
-
+            calculatePrime2MeanFieldType<VolFieldType1, VolFieldType2>(i);
             calculatePrime2MeanFieldType<SurfaceFieldType1, SurfaceFieldType2>
             (
                 i