auto zero touch plate

Is there any calibration that needs to be done on the corner finding touch plate? I am using Mozaik software and the flip parts the tenions do not line up. Mozaik says that the sheet is miss aligned. I ran a test with v carve pro created a tool path in the center of the sheet 24in on the x axis and 48 in on the y and a 1/4 in bit. I ran the tool path and it was 1/4 in off on the y axis. I moved the sheet a 1/2in out of square with the table on 1 side ran the tool path again and it was a 1/2 in off the previous mark. Any suggestions?

I assume you are using the corner finding routine with your tool to find the corner of your material correct?

The corner finding routines i have used in the past find the center of the endmill in realation to the touched off faces, you then have to manually move the zero 1/2 the endmill diameter to be on the true material corner.