Actually I'm finding that with 88/88 (SD defaults) for EEProm steps per MM on the X/Y I'm getting almost exactly 110mm each way when measured with calipers. I'm getting more precisely 110.20 on the Y and 110.41 on the X. But still pretty good I think.

Problem is, the inner boxers are supposed to be 10mm x 10mm and I'm only getting 8.90mm x 9.01mm. What's wrong?

If I adjust my EEProm steps per MM to get 10mm x 10mm on the inner boxes, then my outer dimensions are too large.