It used to be that for PSLF you had to make 120 sequential "on-time" payments and if your loan provider claimed (correctly or incorrectly) that one of them was late then the clock would reset, making it next to impossible for anyone to claim the benefit. A 10-year clock that can be reset at any time by the bank isn't good.

I believe they fixed it (possibly temporarily) so that the clock no longer resets.

This is a partial fix. The full fix would be to have PLSF pay out incrementally, say 10% after each 12 payments.