Opinion......When does the clock start and end on a massage session?

I get incall massage sessions in NYC while traveling.....if I go to someone (incall) and my appointment is at 3pm for a 1 hr session....I arrive 5 minutes early.....never earlier since they might have a client just leaving....so I arrive at 2:55pm for my 1 hr session. After meeting the masseur and being shown to the room I change and get on the table.....by now it is 3:05pm.......my question is:

I booked a One Hour Massage session......should the session go all the way to 4pm? Or should the...

Opinion......When does the clock start and end on a massage session?