If it’s (failure) the case of warped material, the team would like to know, according to Dan.
I do agree that it definitely makes sense to have as flat of material as possible for any type of calibration.
The material height and flatness wouldn’t seem to make a difference. It’s not building a flat map. And it’s not building a database of points across the z-space at different heights. It’s analyzing each snapmark and measuring the height, and ostensibly comparing its actual location to its expected location (from the data in the file).