ups module shipping with set box weights

I have one product with two attributes (12 lb or 22 lb sold in individual boxes). I am using the UPS module and set my maximum package weight for shipping to 22. When someone orders one item, ups figures the rate correctly because it is one box. But when they order larger amounts or 3 of the 12 lb boxes, ups converts it to 2 boxes at 18 lbs. when it should 3 boxes at 18 lbs. If I change the maximum package weight for the 12 lb, it doesn't work for the 22 lb box.
Can someone help me? Thanks

The boxes are based on a calculation ... there is not a setting for actual number of boxes ... as there are no rules setup in Zen Cart to define boxes on a per product basis ...

Ajeh:

The boxes are based on a calculation ... there is not a setting for actual number of boxes ... as there are no rules setup in Zen Cart to define boxes on a per product basis ...

Is there a fix for this? We ship several products that vary in weight and packaging. For instance, we have one product that weighs 18 LB and is in its own "stand-alone" package. If the customer picks this package and another item that weighs 1 LB, Zen charges shipping based on 19LB. UPS however, charges for 1 18LB package and 1 1lb package. The difference is significant! is there any way we can work around this MAJOR issue for us?

Look at another shipping service that uses the total weight of multiple boxes going to the same address? (Fedex - at least they used to)