How to double a shipping surcharge based on item quantity

To the WebAssist Gurus,

I have a question regarding how I can increase a shipping surcharge based on the number of items in the shopping cart. Currently, I have UPS doing the real-time shipping quote for every item in the shopping cart. However, UPS has increased their shipping charges for packages over 48" in width. Any package over 48" inches in width receives a $10.50 surcharge. If someone purchases two of the same item that is over 48 inches long, how can I program the eCart Object to charge this $10.50 surcharge twice? (Or 3, 4, 5 or more times?)

Please see the attached image of how I am currently trying to accomplish this.

However, I am already facing an issue with the way I am approaching this problem. Since I have dozens of items that are over 48 inches in width, if I keep adding conditional statements based on the item number, only one shipping surcharge is applied. For example, if item #20 is added to the shopping cart, then that get's a $31.50 surcharge. Also, if item #21 is added to the shopping cart is, then it should add an additional $31.50 shipping surcharge. The way I have things now, I am only seeing one shipping surcharge in the cart. Just so you know, items #20 and #21 consist of 3 oversized boxes which is why the shipping surcharge is $31.50 and not $10.50.

Any help you can give in trying to get these shipping charges working will be greatly appreciated.

Regards,
Robert