"1. Since it is oft stated that FP is there as a tool for retention it will be argued that, once you have PVR'ed, then the lure of the FP has failed and there is no longer any point paying it."
That also applies to people in their last year till end of commission. Why pay people a retention bonus if they are leaving?
The answer, of course, being that if you started trying that then everybody would resign or stage a coup.