I filed I485 while my I140 was pending. If they have separate line for concurrent filings I should be in the very beginning of it, but no approval so far...
Probably, service center uses average date of the processed petitions to report statistics. To improve look of statistics they could choose to pick some % of cases from 2004. I have Excel file with history of reported I485 “now processing …”. Recent approvals dates for 2002 filers is later then dates estimated using 2004 trend line. That makes me think that progress in processing dates made between 12/17/2004 and 1/6/2005 reports is due to adding 2003/2004 cases.