UG,
To my mind, even if you ultimately ended up leaving, isn't it in your interest to take the PA offer now? For the following reasons:
1. If you were to PVR on day 1 of the new pension you would not lose your flying pay.
2. You would not suffer a reduced pension (PVR rate) on your pre 2015 pension as you did not PVR from it!
Or have I got this wrong?
Regards
RB