RFE is regarding the credibility of processing in EB2..
My I-140 RFE is for providing additional information regarding the credibility to process in EB2 (I don't why they asked at I-140 stage????) such as detailed experience letters that reflects all the job duties I performed at various levels, and any supporting documents such as sealed Masters degree transcript etc..,
My Lawyer responded to that RFE on April 2002, so far no action. Since I got the amended I-140, I stopped bothering about it..