XY plotter 2.0 GRemote jogging

#1

I tested the jogging accuracy in GRemote with dip switch settings set to 1-on 2-off 3-off both controllers and in GRemote set jog xyz to 10 which should move the X and Y axis exactly 10mm but both axis only move 9mm. Why are they off by 1mm? Also the drawing size does not match what is in the g-code.
For example: I25 in the G-code should draw a 50mm OD circle but instead I get a 45mm OD circle. Please advise.

#2