Being as your y moves exactly 1.5" and the X 2" and your microsetting for both axis are the same it looks as if you have different gear ratios driving the leadscrews. The Y might have a ratio of motor 4 revs to one leadscrew turn and the X, 3 revs on the stepper motor to one leadscrew rotation. Try using the axis measurement setting in the motor config setup menus. Might be completly wrong but worth a try.