I've also noticed that the timestamps are off when you run the report.

For example if you run a custom report starting today, (or even if you click on "Today's sales") - you get this for a URL:

/admin/store/orders/search/results/0/0/0/0/0/0/1201248000/1201334399

Unfortunately, that first timestamp - 1201248000 - when you run it through a Unix Timestamp conversion page, returns the value "Fri Jan 25 0800 GMT".

When I look up the first order from this report, the times in the Admin Comments are:

01/25/2008
12:27:10 PM

Obviously this is some kind of math calculation error, and the only way I can see to fix it is to remove the GMT calculation from the reports timestamp.