To make it friendly to Drupal's format_date all I used gmmktime for all date spans in reports, then adjust the time based on Drupal's date & time settings. If I'm not mistaken Fri Jan 25 0800 GMT should = midnight your time, right? That should be correct for the start of the date, though I am concerned about 1201334399 since it should be 1201334400, I dunno.