Does anyone else have an accuracy issue with their big al? I have two, and it seems like it was designed to allow for the thickness of a dull pencil. If I use a knife with it, the lines are actually a little off. If I hold a framing square against the fence, I can see that the edges of the slots are little off the marks on the square. Did I just get unlucky with both of mine, or were they designed this way? CB.