Hmm,
I would suggest you recenter / adjust the piece to the quill before doing the outer circular path. At least it would be symetrical.
If you have scales on the machine you should be able to return to some point and thus you can compare to what Mach's dro's are showing
.......and certainly it should not be 1/4" off........
Check you steps per unit, code , and machine mechanics that all is well.
RICH