If you PVR and leave; spend more than 30 days "out" and then rejoin; elect to repay the gratuity; you will find that the more than 30 days part means you will have to be put on AFPS 05 when you rejoin. Now you are PAS on AFPS 05 and only lost 30 days service.
Of course you may not be offered your job back, but in these times you probably would.