diff --git a/src/OpenFOAM/primitives/one/oneI.H b/src/OpenFOAM/primitives/one/oneI.H
index 3d1e0898de..5be4bc3f88 100644
--- a/src/OpenFOAM/primitives/one/oneI.H
+++ b/src/OpenFOAM/primitives/one/oneI.H
@@ -41,6 +41,30 @@ public:
     typedef arg2 type;
 };
 
+template<class Type>
+inline const Type& operator+(const Type& t, const one&)
+{
+    return t + 1;
+}
+
+template<class Type>
+inline const Type& operator+(const one&, const Type& t)
+{
+    return 1 + t;
+}
+
+template<class Type>
+inline const Type& operator-(const Type& t, const one&)
+{
+    return t - 1;
+}
+
+template<class Type>
+inline const Type& operator-(const one&, const Type& t)
+{
+    return 1 - t;
+}
+
 inline const one& operator*(const one& o, const one&)
 {
     return o;
diff --git a/src/finiteVolume/fvMatrices/solvers/MULES/CMULESTemplates.C b/src/finiteVolume/fvMatrices/solvers/MULES/CMULESTemplates.C
index 9fa61573ed..f43e43e43c 100644
--- a/src/finiteVolume/fvMatrices/solvers/MULES/CMULESTemplates.C
+++ b/src/finiteVolume/fvMatrices/solvers/MULES/CMULESTemplates.C
@@ -233,6 +233,20 @@ void Foam::MULES::limiterCorr
         MULEScontrols.lookupOrDefault<scalar>("extremaCoeff", 0)
     );
 
+    const scalar boundaryExtremaCoeff
+    (
+        MULEScontrols.lookupOrDefault<scalar>
+        (
+            "boundaryExtremaCoeff",
+            extremaCoeff
+        )
+    );
+
+    const scalar boundaryDeltaExtremaCoeff
+    (
+        max(boundaryExtremaCoeff - extremaCoeff, 0)
+    );
+
     const labelUList& owner = mesh.owner();
     const labelUList& neighb = mesh.neighbour();
     tmp<volScalarField::Internal> tVsc = mesh.Vsc();
@@ -331,12 +345,20 @@ void Foam::MULES::limiterCorr
         }
         else
         {
-            forAll(phiCorrPf, pFacei)
+            // Add the optional additional allowed boundary extrema
+            if (boundaryDeltaExtremaCoeff > 0)
             {
-                const label pfCelli = pFaceCells[pFacei];
+                forAll(phiCorrPf, pFacei)
+                {
+                    const label pfCelli = pFaceCells[pFacei];
+
+                    const scalar extrema =
+                        boundaryDeltaExtremaCoeff
+                       *(psiMax[pfCelli] - psiMin[pfCelli]);
 
-                psiMaxn[pfCelli] = max(psiMaxn[pfCelli], psiMax[pfCelli]);
-                psiMinn[pfCelli] = min(psiMinn[pfCelli], psiMin[pfCelli]);
+                    psiMaxn[pfCelli] += extrema;
+                    psiMinn[pfCelli] -= extrema;
+                }
             }
         }
 
diff --git a/src/finiteVolume/fvMatrices/solvers/MULES/MULESTemplates.C b/src/finiteVolume/fvMatrices/solvers/MULES/MULESTemplates.C
index 65b921ed67..251b799a71 100644
--- a/src/finiteVolume/fvMatrices/solvers/MULES/MULESTemplates.C
+++ b/src/finiteVolume/fvMatrices/solvers/MULES/MULESTemplates.C
@@ -224,6 +224,20 @@ void Foam::MULES::limiter
         MULEScontrols.lookupOrDefault<scalar>("extremaCoeff", 0)
     );
 
+    const scalar boundaryExtremaCoeff
+    (
+        MULEScontrols.lookupOrDefault<scalar>
+        (
+            "boundaryExtremaCoeff",
+            extremaCoeff
+        )
+    );
+
+    const scalar boundaryDeltaExtremaCoeff
+    (
+        max(boundaryExtremaCoeff - extremaCoeff, 0)
+    );
+
     const scalarField& psi0 = psi.oldTime();
 
     const labelUList& owner = mesh.owner();
@@ -330,12 +344,20 @@ void Foam::MULES::limiter
         }
         else
         {
-            forAll(phiCorrPf, pFacei)
+            // Add the optional additional allowed boundary extrema
+            if (boundaryDeltaExtremaCoeff > 0)
             {
-                const label pfCelli = pFaceCells[pFacei];
+                forAll(phiCorrPf, pFacei)
+                {
+                    const label pfCelli = pFaceCells[pFacei];
+
+                    const scalar extrema =
+                        boundaryDeltaExtremaCoeff
+                       *(psiMax[pfCelli] - psiMin[pfCelli]);
 
-                psiMaxn[pfCelli] = max(psiMaxn[pfCelli], psiMax[pfCelli]);
-                psiMinn[pfCelli] = min(psiMinn[pfCelli], psiMin[pfCelli]);
+                    psiMaxn[pfCelli] += extrema;
+                    psiMinn[pfCelli] -= extrema;
+                }
             }
         }
 
diff --git a/tutorials/multiphase/driftFluxFoam/RAS/dahl/system/fvSolution b/tutorials/multiphase/driftFluxFoam/RAS/dahl/system/fvSolution
index 95a23401a5..ce36225626 100644
--- a/tutorials/multiphase/driftFluxFoam/RAS/dahl/system/fvSolution
+++ b/tutorials/multiphase/driftFluxFoam/RAS/dahl/system/fvSolution
@@ -26,6 +26,8 @@ solvers
         nLimiterIter    3;
         alphaApplyPrevCorr  yes;
 
+        boundaryExtremaCoeff 1;
+
         solver          smoothSolver;
         smoother        symGaussSeidel;
         tolerance       1e-6;
diff --git a/tutorials/multiphase/driftFluxFoam/RAS/mixerVessel2D/system/fvSolution b/tutorials/multiphase/driftFluxFoam/RAS/mixerVessel2D/system/fvSolution
index 97244e10a1..3e6394c7f8 100644
--- a/tutorials/multiphase/driftFluxFoam/RAS/mixerVessel2D/system/fvSolution
+++ b/tutorials/multiphase/driftFluxFoam/RAS/mixerVessel2D/system/fvSolution
@@ -26,6 +26,8 @@ solvers
         nLimiterIter    3;
         alphaApplyPrevCorr  yes;
 
+        boundaryExtremaCoeff 1;
+
         solver          smoothSolver;
         smoother        symGaussSeidel;
         tolerance       1e-6;
diff --git a/tutorials/multiphase/driftFluxFoam/RAS/tank3D/system/fvSolution b/tutorials/multiphase/driftFluxFoam/RAS/tank3D/system/fvSolution
index 825d041bce..a675081006 100644
--- a/tutorials/multiphase/driftFluxFoam/RAS/tank3D/system/fvSolution
+++ b/tutorials/multiphase/driftFluxFoam/RAS/tank3D/system/fvSolution
@@ -26,6 +26,8 @@ solvers
         nLimiterIter    3;
         alphaApplyPrevCorr  yes;
 
+        boundaryExtremaCoeff 1;
+
         solver          smoothSolver;
         smoother        symGaussSeidel;
         tolerance       1e-6;