I described how to calibrate the axes in this post: Z axis not accurate - #8 by RobertA_Rieke
I’d think your issue had something to do with accidentally using inches instead of millimeters, but I’d expect it to be ~25x larger, not ~5x.
I’m interested to see what your calibration looks like. My X and Y axes calibrations started out at 40 steps/mm, and I think the Z was about 189 steps/mm, with the ACME thread.