I’m not aware of any laws or regulations that limit what a provider can charge a payer. But if the provider is contracted with the payer, then you are usually required by the terms of the contract to accept their fee as payment in full, regardless of how much you charge.
It's going to depend on the payer and your provider contract. Agree with the above advice.
A provider could charge a thousand dollars as the fee on a claim but the reimbursement is still going to be the fee schedule/contracted amount.