IIRC the qualification date goes back to the launch of LSSA. LSA is a modification of the system. It was introduced to ensure that people who go away a lot get progressively more than those who only do the odd OOA tour. The extra levels are funded by the removal of the bonus element of LSSA, which may seem scroogelike at first glance but in reality hardly anyone ever qualified anyway. The good thing now is that any time accrued stays with you forever, unlike the bonus which had a time element. Also levels 1-3 of the new system are the same as the old low, medium and high rates of LSSA so there's a direct read over. The only potential "losers" are the few who would have qualified for the bonus and this will be offset by their moving up levels. For the vast majority its a good change. Could have been better but not really deserving of such a rant IMHO (although if it felt good it probably was good)
Edit. Testing, just noticed you said you had dropped from middle to level 1. I was assured that this wouldn't happen so I'd revisit PSF if I was you.