How auto calibration works

[wzds2015]

Is there any details about run_arm_auto_calibration_moss and run_arm_auto_calibration_so100 we can refer? I read the code but couldn't fully understand.

When should we use auto_calibration, instead of the manual calibration calculating the homing_offset of the rotated (90d) pose?

What to check whether my understanding is correct: for manual calibration, the homing offset include 2 terms, 1) the true offset causing by motor installation, 2) human bias due to manually rotate the motor. If correct, is there a way to also remove the second term? Considering using multiple robots for data collection, guess removing term (2) is required.