Amounts generally billed
Hospital "charges" are fiction: insurers pay a fraction. Section 501(r) says a patient eligible for financial assistance may not be charged more than the amounts generally billed (AGB) — what insured patients' plans actually pay for the same care. If you qualify and your bill is at sticker price, the bill is wrong as a matter of law.
Each hospital computes its AGB percentage from its own claims, using one of two federal methods: the look-back method (what Medicare and/or private insurers actually allowed over a past 12-month period, divided by the gross charges for the same care) or the prospective method (what Medicare or Medicaid would pay for your care today). The percentage and method must be described in the financial assistance policy — the AGB percentage for your hospital is a number you can ask for by name, and many hospitals publish it.
Watch the boundary: AGB caps the hospital facility's charges for emergency and medically necessary care covered by the policy. Separately-billing doctors (anesthesia, radiology, ER groups) sit outside the hospital's AGB unless the policy or state law pulls them in — one reason the itemized bill, and who billed what, matters so much.
Get the HospitalBillDecoded Kit — $49
One payment of $49. No subscription. The kit is a web page you can return to and print — the application pack, the error checklist, the scripts, the deadline tracker, and the escalation ladder.