Tiger, you are missing something.
Leave before your 60th birthday and you don't get your AFPS 15 portion of your pension at 60, you get it at state retirement age. To illustrate this, run the pension calculator with you retiring at 60, and again retiring 1 day before your 60th birthday. The difference is eye watering. The treasury would probably be glad to see you PVR to avoid an LTA breach; they would effectively then start paying your AFPS 15 part of your pension 10+ years later than when you would hoped to have started receiving it!