usually, 485 is filed in the service center which has jusrisdiction over place of employment (future employment). Same goes with I-140, but some companies has this agreement with INS to consolidate and send all their petitions to one service center irrespective of the location of actual job.
I have notices one thing though. If you file 485 with a service center which does not have jurisdiction over your place of living, they send you file (usually) to the local INS office of the area where you live.