I have been using my August 19 2003 as my last entry to US for all my H1B1 application forms. I use this date because I have the official stamp from the custom. Actually I went to Canada for landing in March 15 2004. I have a Canada entry stamp but no US custom stamp with date when I come back to the US.
Which date should I use for my last entry date and last entry place for my I-485 form? If I use the later date, would that raise question from the USCIS because of inconsistencies of my applications? If I use the first date, would that cause my application to be rejected or a RFE?

Which date should I use for my last entry date and last entry place for my I-485 form? If I use the later date, would that raise question from the USCIS because of inconsistencies of my applications? If I use the first date, would that cause my application to be rejected or a RFE?