Need Help with Category Shipping

[dealbyethan.com]

Hi,

I use category shipping and have recently found out a problem. For example, I have Underwear as a category and its subcategories include 2xist, CK and so on. In the admin of the category shipping manager, I have to specify the types of category shipping I want for all the categories and subcategories. If left blank, the shipping will become free. I set up the category shipping in such a way that when someone buys 2 pieces of 2xist (or CK), the first piece will cost $9 and the second pair will be 80% less than $9, so the total is $10.80. This works well. However, if someone buys 1 piece of 2xist and 1 piece of CK, the shipping becomes $18. How do it make the total become just $10.80?

Best regards,
Ethan

[dealbyethan.com]

Hi all,

Does anyone have any idea on how to solve my category shipping issue? At the moment, category shipping suits my store the best but on the other hand it becomes too expensive when someone buys from different subcategories. If they buy from the same subcategory, it works well as the shipping cost is reasonable when the discount applies. Please feel free to go to my site at http://www.dealbyethan.com to do a test and you will know what I mean. Any advice would be appreciated. Thank you. Please let me know if you need me to provide further information.

Regards,
Ethan