As F3sRBest said.
AFPS75 for officers pays an enhanced rate of pension for those officers that leave the service at one of the specified exit dates (ie 38/16, 44(RAF only), and 55). Or it could be, and is, interpreted that a pension on PVR is reduced. The differential between the 2 rates reduces the closer one gets to a full pension (ie 34 years reckonable service for officers).