z height scaling issue

Hello my taz 4 is doing wierd things.
We downgraded from the dual to a single hex.
I have been reflashing with the .hex and also the arduino set of firmware to no avail.
The height of our prints comes out scaled down.
I am to assume the z step of 1600 is consistent and should not be changed.
Here is a picture of a proper print (right) compared to the prints we are getting (left)
Same firmware on other machines has no error.
What could cause this? Thanks!