How long on average for a EB-2 I-140 petition if the USCIS web site says 4 months? Let's throw one RFE to be realistic.

It all depends on the nature of the RFE. For example: RFE issued for evidence of 5 years progressive experience. RFE Response received in Nebraska on 3/30/2012. Approved on 4/6/2012. Another RFE for different employer for multinational executive/manager. Response to RFE received in Nebraska on 3/23. No decision to date but online case status states 60 days from date of receipt.