Thanks for the feedback.

They did assess a separate $75 administrative fee as well as a loss-of-use fee ($110), on top of the diminished value charge and actual cost of repairs ($1,300). They're asking for a total of roughly $2,300.

The local Avis licensee (the vehicle was rented at the Mobile, AL airport) is insisting we pay by check. They could be attempting to guard against the chargeback scenario that was mentioned. It also rankles that they took more than a month to send the documentation and invoice--the car was fixed almost immediately--but are demanding immediate payment.

They cited "a formula established by Crawford & Company, and generally accepted in the industry" for calculation of diminished value. It is 10% of the vehicle cost, plus 20% of the repair bill, with the total being divided by 2.

We've got a business to run and I'm frankly not spoiling for a fight. As a favor to the employee, we're not having him report this to his personal insurance and Amex coverage is secondary, so we're on our own here.