Yes. On the inside, top or back of a mandolin, zero is at the surface, top, of the material. I am trying to get a cut that removes the concavity and leaves the remainder of the wood as is. If I cut just the concavity there is that slightly recessed border cut around the perimeter, If I cut to the edge of the model, there is the slight border cut around the perimeter. That slight border cut is what I am trying to get rid of. The only way I have found to get what I want is to cut to the edge of the material. Takes much longer.