For each type of shipping service we need the option to assign individual Flat Rate shipping Rules.

[bamfcomicsva]

For each type of shipping service we need the option to assign individual Flat Rate Shipping Rules when offered in the same listing. When listing an item we can assign multiple shipping options for the customer to select from but we can only assign a single Flat Rate Shipping Rule so we have to choose the Flat Rate Shipping Rule that charges the most forcing us to overcharge and have to provide shipping discount refunds on many orders while losing sales entirely on others when customers don't realize what's going on.

 We currently have 4 separate shipping options and each has a different cost for adding additional items to ride along. Over time we might even want to offer additional carrier options which could mean even more to pick from.

[rfmtm]

If you are using Flat Rate shipping and this only is for individual listings and not for combining across different listings, why use a shipping rule at all.  Each Flat Rate shipping option allows you to individually select the charge for the first item and also for each additional item using that particular shipping option.

[bamfcomicsva]

It's not complicated.

Buy 1 comic and you have the choice to have it shipped First Class for one price or Priority for a different price depending on what the customer prefers.

Buy two and the First Class Shipping Rule is selected so it discounts the shipping on the second comic to cover the higher cost of the shipping. Unfortunately it also gets applied to the second shipping option, Priority mail which only gets a tiny amount charged for additional items mainly to cover the cost of the board and bag they ship in. 

If they buy 3 comics at the same time, the way I pack to max protect, the weight would exceed what's allowed for First Class weight limits so the additional item charges added to the First Class base now equal the same amount as Priority so I ship Priority.

Any more than 3 items and I'm forced to start refunding. 

Other sites I sell on allow multiple choices for customers to check out by and allow separate additional items rates for each type of service offered. It shouldn't be that hard to implement here.

[bamfcomicsva]

Just yesterday I had to refund one customer for two orders $37.06 and $20.00 in overcharges by E-Bay's setup. 

[rfmtm]

I may be missing something, but yes, a shipping rule applies to all shipping options in the listing, so don't use a shipping rule, then additional items charges can be different for each shipping option in the listing.

Shipping option  1. FCP  first item $5, additional item $2. (at three the shipping is $9 for Priority, if more than three, buyer will see it is cheaper to select Priority)

Shipping option 2. Priority first item $9, additional item $.50cents.