Suggestions in calculating shipping on larger items

I have a wide variety of sizes of products that I ship out. Ranging from things like resistors and capacitor all the way up to full size guitar speaker cabinets. Some of the speaker cabs are not being calculated correctly.

For example:
Cabinet Weight: 32 lbs
Zen Cart UPS Module: $22.50
Actual UPS Cost: $41

Got any suggestions on alternative ways to handle shipping?

All the smaller items are calculating just fine. There are also some larger cabs that qualify as oversize 2.

If larger pkgs are all a certian $ amount or % off you can adjust in
admin > config > shipping > Larger packages - added packaging percentage:weight

If they are not calculatable, then for the disparity you noted it seems that a paid module would pay for itself rather quickly

Google for "zencart advanced shipper" - - many have touted it's features

So how do I go about creating the formula? Sorry its a little confusing, need more coffee this morning. :)

For example
Items that are 25 - 50 lbs?
Items over 51 lbs?

So how do I go about creating the formula? Sorry its a little confusing, need more coffee this morning. :)

For example
Items that are 25 - 50 lbs?
Items over 51 lbs?
What additional percent are you requiring???

Umm I am guessing 15% for 25-50 and 10% for 51 +

Zen Cart UPS Module: $22.50
Actual UPS Cost: $41
This is way more than 10 or 15%