I think there may be some confusion with FTRS and Rejoin here.
If in receipt of a pension it is stopped on rejoining - simple. There is then a repayment due IF resettlement commuation was taken (APFS75 stuff) because you are not resettling - the MOD has given you your old job back.
FTRS pay is capped at the level that you left at - you cannot earn more than on the last day of service.
If in receipt of a pension then that is used to make up your salary and the MOD tops up to the level that you left - ie you are paying yourself.
Can't see the attraction.
Who wins? Senior officers that take on the responsbility of a junior.
Creating a load of clockwatchers and contract readers...Discuss.