So the upper classes just get money on an individual performance basis, but only Class D is stuck working collectively? That nearly breaks suspension of disbelief right then and there.

It has to work that way, obviously, because otherwise there wouldn't be any money to spend on Class D members humiliating themselves for points after they run out of them.

I get that this is some Machiavellian shit to produce the most elite students possible, but the premise sort of breaks apart right from the start.