Errr, I don’t think you understand what Commutation is! This sees a reduction of monthly pension until age 55 to pay it back - regardless of whether you re-join, go FTRS/ADC or do something else. The thing that is affecting you as a rejoiner is the abatement rules, which is the same for all public sector pensions. It’s a HM Treasury rule. Also, for those on AFPS05, that rejoin regular or FTRS/ADC, then abatement is 100% of the EDP (ie. you get no payments until you retire again).
So as JTO points out - make sure you read up on this or speak to people like the Forces Pension Society if you can’t be bothered to read it for yourself.
https://www.gov.uk/guidance/pensions...n-for-veterans