Sorry to butt into the civ/mil debate (which I was enjoying), but I'd like to have a go at answering the original question with some facts.
Most of this is old news - the figures being quoted (6 years to lose FP) are the old deal. The Pay & Allowances Review knocked that on the head in Spring. The new deal is 2 years not in a Flying Related job at 100% and you lose 50% in Year 3 then 100% in Year 4.
Whilst this is pretty galling if you're sent to 2 consecutive tours away from a Flying Related job, you'd have to be trying pretty hard to achieve this. So the reality is that almost everyone currently in receipt of FP is staying on 100% at the moment.
Will it stay that way until Christmas? I wouldn't bet my Flying Pay on it (but then, since I'm not in a Flying Related job at the mo; I guess that I sort of am!!)