As others have said, it is customer's decision and of course, can be updated. Ours for out (chocks off) time is brakes off and aircraft movement. Time on chocks, however, is recorded at last parking brake application before first cabin door is opened. As we are still in charge of the aircraft if for example, ground staff take their time in placing the jetway/airstair into position, we do have a little fun of our own with the parking brake in the meantime
