L J R, the reference doc is JSP754 Edition 6. The rules haven't changed since edition 3 which replaced AP3392 with the intro of JPA. The following should answer your concerns:
Premature Voluntary Retirement
05.0621. The pay of PAS personnel will not reduce on approval of an application for premature voluntary retirement (PVR).
Pensions
05.0622. Under AFPS 75, pensions for PAS personnel will be enhanced by adding a daily supplement to the standard representative rank based pension that an individual is entitled to on leaving the Services. For RAF PAS OF2s, this will be the standard Specialist Aircrew (SA) representative rank based pension and for RAF PAS OF3s this will be the standard CS representative rank based pension. For RN and Army PAS/PES(A) OF2s and OF3s this will be the CS standard representative rank based pension. The supplements will be calculated each year to reflect the pension headroom differential between the normal maximum representative pay rate for rank and the maximum pay point on the PAS that an individual can reach. The appropriate daily supplement will be earned for each day of service on the PAS, provided that a minimum of 5 years paid and pensionable service on PAS terms has been given before retirement. The pension supplements are promulgated annually by Directed letter.
05.0623. RAF PAS OF2s who exit the Service prior to giving the requisite 5 years of service on the PAS will receive the standard SA representative pension based on rank without any supplements. RN and Army PAS/PES(A) OF2s who exit the Service prior to giving the requisite 5 years of service on the PAS/PES(A) will receive the standard CS representative rank based pension. PAS/PES(A) OF3s who exit the Service prior to giving the requisite 5 years of Service on the PAS/PES(A) will receive the standard CS representative rank based pension.
05.0624. Pensions for those serving under AFPS 05 will be based on the final pensionable salary; there are no supplements payable under AFPS 05.
Personally I have 'set' my PVR date after 5 yrs as PA. The online calculator does not work for this situation. The pension prediction from Kentigern House was within a few £s of my own calculation of service and supplement rates. Bottom line -no penalty for PVR after 5 years service on AFPS75.
As an aside, I will greatly miss all the excellent friends and colleagues that it has been my good fortune to work with over the years but I am being 'forced' to leave for all the good reasons that have been eloquently stated on other threads.
CC