Do I need to response to the EB1a I140 RFE after NIW I-140 appro

I co-ted my I140 (EB1a and NIW) and 485 in Sept 2005. Recently my NIW I-140 has been approved but Eb1a I-140 is required for RFE. My question is should I still try to get this Eb1a approved so that my 485 processing can be started earlier.The visa bulletin for Eb1a is current while for NIW is only Mar2005 now, does that mean even my NIW 140 is approved, my 485 processing have to be still suspended until my priority date becomes current? However, if the Eb-1a is approved, my 485 processing can be started immediately since the visa bulletin for Eb-1a is current.Is my understanding correct?

Thanks a lot