It seems very misleading to say that they are being paid $X/hour if the denominator is supposed to represent the number of class hours rather than the number of hours worked actually spent working. Everyone will assume the latter, so you should be explicit about that.
As everyone who has done any teaching knows, the time spent standing in front of a class is just a small part of the total required time.
Yes I do understand it, but it's the way they were giving out contracts at the school. I've seen one of them. It just says something like. You will be paid xxx$/h. Your course A has 40 hours. Your course B has 60 hours.
I mean it's fine for the contracts to be worded like that, it's spelled out and both parties understand it. It's confusing for you to come here and say that teachers make $100/hour, because people will assume that you mean for each hour worked. You should try to convert your numbers into the units that everyone else is using.
As everyone who has done any teaching knows, the time spent standing in front of a class is just a small part of the total required time.