The magic number for the SM2 is 0.04mm so why are the TS and Luban set for movements that are not a multiple of the 0.04mm magic number? This may be part of the issue with backlash and inconsistency in the bed leveling routines.
Justification for the magic number:
Stepper is 1.8° per full step
Leadscrews in the motion modules are 2mm pitch 8mm lead (4 start)
Firmware is set to 400 steps per mm and 1/16 microstepping (limit of the Toshiba stepper drivers used in the motion modules and also limit of the A4988 used in the extruder module) (also explains why the machine is so loud)