WP eCommerce plug-in and the UPS API?

I have an existing client website that the live UPS shipping is not accurately calculating so the client is losing money on each order. It's a very odd problem as the product dimensions and weights are set up in WP e-Commerce and we're using the client's UPS account and API # to calculate the "live" rates at time of order. But when the log into their UPS account upon receiving an order and enter the exact same product dimensions and weights, the actual shipping total is higher -- thus their losing money on almost every order. And I can't identify a pattern to it where we could just have it add a "handling fee" to each order. I need to solve the issue so that what the shipping calculates at time of order is accurate to the actual shipping cost. The client's website is [login to view URL] and the e-commerce is all under Products. The client tells me that every order they have received thus far is off, regardless of the product. I'm not sure what info you'll need for testing and comparison so just let me know. Also, it's important to note that a couple of months ago I had another programmer do some custom work to the WP e-Commerce files so that the cart would pass along each product as a separate "line item" to the UPS API so that UPS would return the shipping cost for each item -- rather than based on the entire order. Each of their products ships individually, but what was happening, by default, was that the total weight of the entire order was greater than the 150 lb. weight limit from UPS so UPS would either return an error -- or a $0.00 shipping cost to the cart. The fix that that the programmer applied corrected this so that no matter what quantity of products are ordered, UPS would calculate the shipping on each item individually and then return the total shipping amount to the cart. The file that the programmer made the fix to is in the WP e-Commerce plug-in folder > Shipping > [login to view URL] (and possibly [login to view URL]). I wanted to mention that so that 1) you can check those files to see if anything was coded incorrectly or needed to be adjusted; and 2) so that you would be aware not to overwrite those files for some reason without realizing they had been altered for this reason. Just as some additional information, I was talking with the client just now. It seems in the current setup, that increasing the product dimensions has no effect on the shipping calculation. For example, just as a test, the client's IT person increased on of the products from 6 inches x 6 inches to 16 inches x 16 inches (kept the height and weight the same) and it did not make a difference in the shipping calculation. So his theory is maybe the calculations are being made on weight only and not taking into consideration the dimensions, like happens on [login to view URL] while logged into their account. I don't know - just wanted to pass that along if it could offer any insight into the overall issue. Also, to clarify, each product should be treated as an individual item to be shipped. So as an example, if one item costs $10 to ship based on it's length/width/height/weight/shipping destination -- then 10 of the same items should cost $100 just as if they were ordered one at a time. "On the last order we had for 4 of the MyTheater 24" x 40" 2-pk panels, each box cost us $14.90 to ship via UPS using PayPal shipping for a total of $59.60. We collected $48.56 for shipping from our website. Below are the rates according to the shopping cart to the same address. 1 box - 15.62 2 boxes - 28.17 or 14.09 each 3 boxes - 39.16 or 13.05 each 4 boxes - 48.56 or 12.14 each 5 boxes - 53.11 or 10.62 each As we discussed this morning, the shopping cart should look at each item and each quantity as a separate shipment when requesting rates from UPS. Then total the rates in our shopping cart code if possible. Also, we need to make sure it sends the dimensions to UPS when requesting rates. We should be able to change the size only for an item and see a rate change.