At this stage I'm thinking you may be right.

Doesn't really explain this :

> eBay Stores selling fees for managed payments sellers

right down the bottom of the page :

> Fees for using PayPal

> We don't charge fees for using PayPal on eBay. However, if you accept PayPal payments, PayPal will charge a fee when you complete a sale, and the buyer pays with PayPal.

But I think patience isn't going to be key here.