diff --git a/tutorials/incompressible/icoFoam/mixingPlane/twoBlocksMixingPlaneMismatch_dirY_spanZ/0_orig/U b/tutorials/incompressible/icoFoam/mixingPlane/twoBlocksMixingPlaneMismatch_dirY_spanZ/0_orig/U
index c9b0cd956..e5afe4b5d 100644
--- a/tutorials/incompressible/icoFoam/mixingPlane/twoBlocksMixingPlaneMismatch_dirY_spanZ/0_orig/U
+++ b/tutorials/incompressible/icoFoam/mixingPlane/twoBlocksMixingPlaneMismatch_dirY_spanZ/0_orig/U
@@ -54,12 +54,6 @@ boundaryField
         type            mixingPlane;
     }
 
-    top
-    {
-        type            fixedValue;
-        value           uniform (0 0 0);
-    }
-
     frontAndBack
     {
         type            empty;
diff --git a/tutorials/incompressible/icoFoam/mixingPlane/twoBlocksMixingPlaneMismatch_dirY_spanZ/system/controlDict b/tutorials/incompressible/icoFoam/mixingPlane/twoBlocksMixingPlaneMismatch_dirY_spanZ/system/controlDict
index 44f894261..ddd443c2f 100644
--- a/tutorials/incompressible/icoFoam/mixingPlane/twoBlocksMixingPlaneMismatch_dirY_spanZ/system/controlDict
+++ b/tutorials/incompressible/icoFoam/mixingPlane/twoBlocksMixingPlaneMismatch_dirY_spanZ/system/controlDict
@@ -24,7 +24,7 @@ stopAt          endTime;
 
 endTime         5.5;
 
-deltaT          0.005;
+deltaT          0.001;
 
 writeControl    timeStep;
 
diff --git a/tutorials/incompressible/icoFoam/mixingPlane/twoBlocksMixingPlane_dirY_spanZ/0_orig/U b/tutorials/incompressible/icoFoam/mixingPlane/twoBlocksMixingPlane_dirY_spanZ/0_orig/U
index c9b0cd956..e5afe4b5d 100644
--- a/tutorials/incompressible/icoFoam/mixingPlane/twoBlocksMixingPlane_dirY_spanZ/0_orig/U
+++ b/tutorials/incompressible/icoFoam/mixingPlane/twoBlocksMixingPlane_dirY_spanZ/0_orig/U
@@ -54,12 +54,6 @@ boundaryField
         type            mixingPlane;
     }
 
-    top
-    {
-        type            fixedValue;
-        value           uniform (0 0 0);
-    }
-
     frontAndBack
     {
         type            empty;
diff --git a/tutorials/incompressible/icoFoam/mixingPlane/twoBlocksMixingPlane_dirZ_spanY/0_orig/U b/tutorials/incompressible/icoFoam/mixingPlane/twoBlocksMixingPlane_dirZ_spanY/0_orig/U
index c9b0cd956..e5afe4b5d 100644
--- a/tutorials/incompressible/icoFoam/mixingPlane/twoBlocksMixingPlane_dirZ_spanY/0_orig/U
+++ b/tutorials/incompressible/icoFoam/mixingPlane/twoBlocksMixingPlane_dirZ_spanY/0_orig/U
@@ -54,12 +54,6 @@ boundaryField
         type            mixingPlane;
     }
 
-    top
-    {
-        type            fixedValue;
-        value           uniform (0 0 0);
-    }
-
     frontAndBack
     {
         type            empty;