Anyway, of course there are no "rules".
It has happened to me a few times that an hour booked with a masseur at a low, price or higher price (from 100 to 180 in my experience and in my budget) has turned into a full service (from unexpected very sensual to outstanding passionate f*cking), and I never pointed a gun or forced any of them to do something they didn't feel doing, of course.
Other times it has remained a generic pleasurable "sensual" massage" and a few times a disappointedly "mechanical" one.