Hmm, if I'm wrong in some assumption point out where I err because I don't see it. The date range in the search URL looks for orders between

1201248000 (Fri, 25 Jan 2008 08:00:00 GMT = Fri, 25 Jan 2008 00:00:00 PST) &
1201334399 (Sat, 26 Jan 2008 07:59:59 GMT = Fri, 25 Jan 2008 23:59:59 PST).

The UNIX timestamp doesn't adjust based on timezone so searching orders with timestamp range should return all orders that happen on 1/25/2008 for PST.

So there are no orders showing up earlier than 12:00 PM your time? I think the search orders form restricts itself to orders with a particular status. Could you plug that date range in a SQL query on your uc_orders table? Otherwise, I don't understand why that timestamp range wouldn't yield all orders created on 1/25/2008 for PST.