Many of the providers we begin working with believe they should be collecting the ‘disallowed’ amount (the difference between their full fee and the allowed amount) from their clients. This is 100% considered insurance fraud and it’s critical to not do so!
The allowed amount as posted on an EOB is the maximal amount you can collect from the combination of the insurance company and the client. Any more collected from the client beyond that allowed amount is a breach of your contract with that insurance company, either in or out of network, and must not be done!
I cannot emphasize how important it is to not make this mistake and it’s definitely a common practice that we do regularly correct with our new providers (who never mean anything malicious, they simply don’t know or heard so from a colleague).