In the Advanced Compass Setup Document , under CompassMot Calibration details it says if magnetic interference is higher than 60% you should try moving
your APM/PX or External GPS/Compass Module further up and away from the sources of interference.
So the CompassMot is only for monitoring not Calibration, just like Battery Monitoring.
Finally in my opinion , the CompassMot Calibration should be renamed as CompassMot Monitoring.
Could anyone argue or disargue with my opinion?