I work for a large hospital, and we do have a sliding scale for uninsured patients. I also worked for a profee firm, who also offered a discount for uninsured. Since they have no insurance, they can not be bound by any rules or contracts that I would know of. It is their money, and CMS is not involved.
First do not confuse a hospital with a physician when it comes to billing and regulations. A hospital was built with public funds and is therefore required to give back in the form of discounts and charitable care. A physician is not allowed to do these things. Second, just because the practice is done does not make it right.
It does not matter that the patient does not contract with insurance, the fact is the physician office does and is therefore bound by all state and federal laws that govern billing.
There is a very important clause the barring all else Medicare can fall back on called the Most favored Nations Clause. It is a legal clause that in effect states:
In health law, the clauses are sometimes called "equal rate" or "comparable rate" provisions because they require doctors to let plans match, not beat, any lower reimbursement rate from another insurer. These clauses typically require a provider to give the payor the lowest rate that it gave to any other comparable payor. (a self pay patient is also a payor).
Another source will state it as you may not charge any one entity an amount that exceeds the what you charge to the least charged entity for the same service.
Now my question to the original poster is were you speaking of down coding or discounting? Downcoding is charging for a lesser service than what is documented, and that you can never do.
Discounting services is not allowed on a routine and regular basis. If you have a patient that cannot afford the care given you may follow the states medical indigency provision and discount by the amount allowed by the state but you must have proof of the patient income and that they do not qualify for Mcaid.