The effort to handle a chargeback is not proportional to the amount of the charge, so I don't see why the fee would be. If you read around on retail forums, yo

The effort to handle a chargeback is not proportional to the amount of the charge, so I don't see why the fee would be. If you read around on retail forums, you'll find that nobody would be able to get away with anything close to a 7% chargeback rate with traditional credit card processing, without getting their merchant account terminated with severe prejudice -- anything more than a percent or so raises alarm bells with the card companies.