My store is currently running on Zencart 1.3.8a.

A customer ordered two products yesterday with UPS overnight shipping. Zencart calculated shipping weight at 5 pounds, and charged the customer $66.80. When I packed the shipment, it was only 4.5 pounds, but UPS.com charged me $73.56.

I sent an email to UPS tech support, and they said, "Thank you for your inquiry. Without all of the details I will not be able to figure out what is making the charge different. it is possible that the shipping module is not set up for 2008 rates?

To find out you can contact technical support at 877-289-6418."

I called UPS tech support, and they told me they only provide support for UPS.com, and couldn't help me.

I checked the UPS shipping module setup and can't find anywhere to adjust shipping rates. It was already set up to charge a residential surcharge.

Is there anything I can do to make the UPS shipping module calculate prices better?