Another post on this very topic that may help is here:
http://forum.ppcgeeks.com/showthread.php?t=101460
Regarding "time sync" in phone setup... I ALWAYS turn it off 1st thing on any new ROM, it seems to be an old fix for a very old problem of hyperactive active sync... although it helps, active sync still autostarts way too often. I think I'll nickname it "hyperactive sync". ha! a-d-d sync, Ritalin sync..
My take? DST (Daylight Savings Time) issues based on the change a couple years ago & perhaps in addition, the issue in SP2 of XP.. a combo of both & when the patches were applied (calendar events already set).