gcdilemma,
I wrote a check in my Lawyer's name and he wrote his own check to USCIS. So I am not sure when was that check encashed.
However, USCIS received the reply on 2/5/2004 and the case got approved on 3/23/2004. Consider approximately two months after receipt of Supplement A to I-485 with $1000 check.
Thanks
-TRISAM