Hi,
I found this on a hunt for answers, my cncest 3040T was ramping rapidly, I checked the settings and z was way off. So I reset all to 400 1500 400.
But Z is still ramping slightly from 0.000 start at stock point, after 180° return to zero it reads 0.0025 but its actually 1.0025mm.
It's the 800w machine with the water cooled spindle motor.

Is it the first block or third block of numbers I need to change in motor tuning to try and keep it level?

If it's a straight radial cut it's fine. But there are rises and dips in the model so it's after repeated direction changes it runs off.