Combined shipping calculator is not working correctly

[pd1224]

I've had two buyers request combined shipping recently. One purchased baseball cards and one purchased vinyl records. When they submitted for combined shipping, the calculator simply doubled the postage charge, defeating the purpose of combined shipping. It does not cost twice as much to ship two of either of these items. It would appear that the post office is the beneficiary of this mistake.  Any thoughts/advice?

[disneyshopper]

https://www.ebay.com/ship/prf

You need to create a RULE for combined shipping.  My rule is to ADD THE WEIGHTS because I use calculated shipping on all my listings.