shipping costs

I am going to a new drop shipper who calculates shipping costs based on categories. I feel these costs are too high and have nothing to do with product weight or dimensional weight. Is there a module or plug-in to CubeCart I can add that will more accurately reflect the cost of shipping?

Buyers, as you know, are very sensitive to shipping costs and is a major factor in determining a purchase.

Your knowledge and experience is appreciated.

See if you can set up your own account with UPS (or whoever) and have the supplier ship using your account. That way, you only get charged the actual freight.