I’m having problems with the shipping algorithm for the USPS module. I believe I have conclusively proven that the problem is in Viart's coding, not in any of my settings.
 
When I have a shopping cart that meets the following simple criteria, the error occurs:
 
* One or more USPS shipping methods available for ship-to address
* Quantity of items in cart is greater than 1
 
The error is as follows:
 
Each item is considered a separate package. Thus, the shipping charge for each item is calculated separately and added together. This results in shipping charges much higher than proper.
 
I have already upgraded to the USPS 4.0 patch on one of my web sites and that did not help. I also upgraded another site to 4.0.6 (from 4.0.5) and that did not help either.
 
You can experiment for yourself at www.copiermanual.com or www.inkjetprinthead.com. (Please note that on these web sites, the USPS module is only used for international shipments. So to see it in action, you have to choose an international ship-to country. But by temporarily turning on the USPS module for domestic addresses, I was able to demonstrate to myself that the error will occur for domestic addresses as well.)

Fixed!!! Thanks to help from Viart. I didn't know how to use the "number of packages" field in the item specs correctly. If it's empty, it defaults to 1. I changed it to .05 for all my items and all is well now!