As a side note, in my experience Paypal does keep their transaction fees even when processing a refund. How does this behavior differ from what people were incorrectly accusing Apple of doing?
1. Apple has a monopoly on sales of iOS apps. If PayPal does something you don't like, you can leave them for their competitor and still keep providing the same products and services to your customers. If Apple does something you don't like, you need to either put up with it or abandon your iOS customers.
2. PayPal's fee is an order of magnitude less than Apple's fee.
3. PayPal usually has actual costs when someone buys and refunds something, since most consumers don't keep a balance in their PayPal account. Apple usually doesn't, since a lot more consumers do keep a balance in their iTunes account (from, e.g., gift cards).
