I received my EB-1(a) status in Sept. 2005. The process went VERY fast. (6 weeks from start to finish). However I did receive one letter asking for additional info. I did not have any additional info., if I did have it, I would have sent it in with the first batch. My lawyer sent back a letter bascially saying, that's all there is (and it was alot). I got my next (approval) letter from USCIS a couple weeks later. If you do not have any addtional info., don't sweat it too much.
Jeff
Jeff