I uploaded a board from Eagle, which seems to have used about .2" offsets on X/Y. I see this in Viewmate and when I upload to the DRC bot. However, the DRC bot thinks the X origin is 0, so it gets the board size wrong. It was rounding from 1 sq in to 2, so I noticed. I made the board smaller several times before I figured out what was really going on. I finally made the cam tool move -0.15X to get under the 1 sq in. Xmin did not go negative, supporting my theory. I had also hand checked all X coordinates in the files to make sure none were actually at 0.
(when I did finally get to 1 sq in, the web page said it would cost $2 instead of $2.50!)