Hi @adrienlucca,
Cool experiment!
Do you mind me asking, did you try the correction on pieces of various sizes and located in various places across the wasteboard ?
As someone who spent waaaaay too much time about X/Y calibration and mapping (as in, really going too far), I would be interested to know how well the corrections values hold across different sizes and locations. My own conclusion in the end was to leave this alone, let the X/Y steps to their default values, and deal with precision at project/CAM level (that said, the squaring of my machine is pretty good, so that helps)