diff --git a/dumux/freeflow/navierstokes/staggered/fluxoversurface.hh b/dumux/freeflow/navierstokes/staggered/fluxoversurface.hh
index 5191502f46c45a7058b63e393a589a8123230c86..c26b6cb6344219c4e8ecd7f766a055e6f3551857 100644
--- a/dumux/freeflow/navierstokes/staggered/fluxoversurface.hh
+++ b/dumux/freeflow/navierstokes/staggered/fluxoversurface.hh
@@ -250,7 +250,10 @@ public:
                                const auto& elemFluxVarsCache)
         {
             CellCenterPrimaryVariables result(0.0);
-            result[0] = elemFaceVars[scvf].velocitySelf() * scvf.area() * scvf.directionSign();
+            const auto& insideVolVars = elemVolVars[scvf.insideScvIdx()];
+            const auto& outsideVolVars = elemVolVars[scvf.outsideScvIdx()];
+            const Scalar extrusionFactor = harmonicMean(insideVolVars.extrusionFactor(), outsideVolVars.extrusionFactor());
+            result[0] = elemFaceVars[scvf].velocitySelf() * scvf.area() * extrusionFactor * scvf.directionSign();
             return result;
         };
 
diff --git a/dumux/multidomain/boundary/stokesdarcy/couplingdata.hh b/dumux/multidomain/boundary/stokesdarcy/couplingdata.hh
index 364e7d7e8776c5e66ce909723f8c50b8b4b7b302..854fa853bcdbf18d792115a7b59afc80db9db45c 100644
--- a/dumux/multidomain/boundary/stokesdarcy/couplingdata.hh
+++ b/dumux/multidomain/boundary/stokesdarcy/couplingdata.hh
@@ -406,8 +406,8 @@ protected:
                                              domainJ,
                                              insideDistance,
                                              outsideDistance,
-                                             thermalConductivity_(volVarsI, fvGeometryI, scvI) * volVarsI.extrusionFactor(),
-                                             thermalConductivity_(volVarsJ, fvGeometryJ, scvJ) * volVarsJ.extrusionFactor(),
+                                             thermalConductivity_(volVarsI, fvGeometryI, scvI),
+                                             thermalConductivity_(volVarsJ, fvGeometryJ, scvJ),
                                              diffCoeffAvgType);
 
         return -tij * deltaT;
@@ -1026,10 +1026,7 @@ protected:
         }
 
         Scalar omegai = 1/insideDistance;
-        omegai *= volVarsI.extrusionFactor();
-
         Scalar omegaj = 1/outsideDistance;
-        omegaj *= volVarsJ.extrusionFactor();
 
         reducedDiffusionMatrixInside.invert();
         reducedDiffusionMatrixInside *= omegai*volVarsI.molarDensity(couplingPhaseIdx(domainI));
@@ -1095,8 +1092,8 @@ protected:
                                                        domainJ,
                                                        insideDistance,
                                                        outsideDistance,
-                                                       diffusionCoefficient_(volVarsI, couplingPhaseIdx(domainI), domainICompIdx) * volVarsI.extrusionFactor(),
-                                                       diffusionCoefficient_(volVarsJ, couplingPhaseIdx(domainJ), domainJCompIdx) * volVarsJ.extrusionFactor(),
+                                                       diffusionCoefficient_(volVarsI, couplingPhaseIdx(domainI), domainICompIdx),
+                                                       diffusionCoefficient_(volVarsJ, couplingPhaseIdx(domainJ), domainJCompIdx),
                                                        diffCoeffAvgType);
             diffusiveFlux[domainICompIdx] += -avgMolarDensity * tij * deltaMoleFrac;
         }