Will calibrate to 1 inch, but no where else

[Bell 430]

Hello folks
I have a 2008 Shopmaster eldorado bridge mill, it came with CNC installed from the factory. I just upgraded from acme screws to ball screws.
While the acme screws were installed I had .002 in all three axis.
Now with the ball screws installed i cannot get it to "Calibrate" I've checked the machine for mechanical items, there all good.
Heres my problem:
If I command G01Y-1 from zero the table moves exactly 1 inch, confirmed both by dro and dial indicator. if I command g01y0 it goes back to zero. BUT if I command g01y-.5 it comes up .010 short. if I command g01y-.7 it comes up .007 short, it keeps "Creeping" up with each move. if I go from g01y-1 back to g01y-.5 it comes up .010 short. and so on untill its back to zero. I've tried with backlash set to .004 and shuttle accel speed in general config to .005. the .004 is being corrected, eg if commanded to g01y-1 it goes to 1.004
if i do the other commands it follows, the .004 is at each move.
Just more info, it does the same thing in ALL axis, and either the positive or negative direction
I hope this wasn't too long, but please help
Thanks
Brian