diff --git a/Source/func.f90 b/Source/func.f90
index e8815a62d62..c0a4057aa34 100644
--- a/Source/func.f90
+++ b/Source/func.f90
@@ -2729,7 +2729,8 @@ SUBROUTINE GET_WALL_NODE_COORDINATES(N_CELLS,N_CELLS_OLD,N_LAYERS,N_LAYER_CELLS,
    ENDDO
    IF (N_LAYER_CELLS(NL) > 0) THEN
       II = II + 1
-      X_S(II) = X_S(II-1) + LAYER_THICKNESS(NL) - DX_SUM
+      DX_S = LAYER_THICKNESS(NL) - DX_SUM
+      X_S(II) = X_S(II-1) + DX_S
    ENDIF
    IL = IL + N_LAYER_CELLS_OLD(NL)
 ENDDO