One thing I find very odd about this: it’s in both parties’ interest to gave as much tuition remission as possible and as little pay as possible: tuition remission is not taxable. The deal should have been that tuition remission depends on hours and the hourly pay goes way up after there’s no tuition left. Maybe this violates the Fair Labor Standards Act?
When I was a TA, the effective hourly pay was in excess of $70. It was an amazing job!