Like GlassCollector says, it's a non event. Your 38/16 point remains an optional retirement date that you can take with 12 months' notice, so you don't lose that out (and if you do take it, you still get your pension on compulsory retirement terms, not PVR terms).
If you do decide to stay an extra couple of years (exact figure depending on your and your circumstances), then on retirement you'll get a slightly larger AFPS75 pension if your pay's increased, and you'll also get AFPS15 EDPs rather than having to wait until age 60 to get anything from that section of your pension.
If you're in the PAS bracket, PAS terms (this year at least) stay the same, so if you get an offer it'll take effect at your 38/16 point and the 5 year amortisation period starts then too.
I'm not in the bracket and didn't receive one, but from talking to colleagues who're approaching that stage at length there seems to be literally no reason not to take it right now, considering it doesn't remove your 38/16 point.
The only negative I can see is if you're considering PAS and you're not going to feature on this year's board, then you'll end up shifting the start of your PAS career to the 20yr service point.
Hope I'm accurate; the above represents the collective crewroom wisdom of my squadron!