Yes, FP date does matter in a sense.
But the cases are assigned according to the RD/ND, not FP date.
The FP date matters in a sense that it could slow down the process
of your case if by the time an officer picks up the files the FP
result is not there. My point is, as long as your FP result is ready
before the case is assigned ( which is NOT based on FP done dates ),
everything should be OK. If you feel that you are waiting too long
( since probably your FP was not ready when your case was assigned ),
you should try to speak with an IIO to find out why, and chances are
s/he might go check for you and pull out your files from the backlog shelf... Good luck!