Klugeryid, what you describe is not an hourly rate, it’s an annual salary. A $55K salary for 950 hours worked comes to $57.89 an hour, but that’s not the rate, it’s just what it happens to come to. The pay stub is unlikely to mention hours at all, because they’re not being paid by the hour. If the school is now demanding more work for the same pay, so what?
Alternatively, they may be paid by the hour, and the school has just told them that next year the rate will be cut, so that they will have to work more hours to earn the same amount they did last year. Again, so what? So long as they’re free to quit it’s not slavery, and so long as this takes effect only after the announcement, not retroactively to hours already worked, it’s not theft.