My two cents:
My operator flyes A318, A319 and A320, and the discrepancy between GW (FMGS) and GWFK (AIDS) has some slight variations (normaly AIDS weight is slightly larger) but in the A318, the difference is usually more than 4 tons! A bit worrying. Also the A318 descend profile always is too low, the airlane going too slow/too low.
Regards