I understand LJ's frustration. You don't need financial advice to understand the simple fact that your AFPS75 rights were/will be preserved on transfer, to AFPS05 (if you took it) and AFPS15 (whether you end up taking it in 2015 or 2022).
Forces Pension Society:
All pension earned up to 31st March 2015 in a legacy scheme became an accrued pension right that can’t be taken away.
If you have AFPS75 in your pension history then you will get a AFPS75 lump sum on retirement. The more years you had on AFPS75, the bigger it will be. It really is as simple as that.
If you are not confident in your ability to use the pension calculator to make projections, then a financial advisor will help you work out which of the AFPS15 transfer points you should opt for, and whether you should retire a few weeks before your mandatory date. Those are decisions you can take nearer the time.
For the avoidance of doubt *
your earned pension rights cannot be taken away and there is no need to leave the service to protect them*.