Final Value Fees based on when item was lited, not on when Store was opened

[tahoesilvercc]

I recently opened an Ebay Store and rolled my previous listings into that Store. I just received my Ebay invoice and saw that I was being charged the 10% Final Value Fee for items that were listed before I opened the store but sold after the store was opened. Ebay Customer Service claims that the rules at the time of listing apply to those items, not the terms of the Store (6% FVF instead of 10%). I have asked Customer Service to show me where it says that in their terms and policies but they have not been able to produce anything on their site.

They sent me an email where that was typed up in the email but no link to their website where it actually states that. I think they made it up.

Does anyone know for a fact if items listed prior to opening a store fall under store rules or the rules that applied at the time of listing?

Thanks!