(a) If a physician, medical facility or other provider of medical treatment receives notice from a municipality that, pursuant to an ordinance enacted under Section 22-306 or under its home rule powers, the municipality is willing to assume liability for all or part of the medical expenses of a policeman or firefighter injured in the line of duty, and if the provider consents to such assumption of liability by the municipality for all or part of the cost of the medical services being provided, then the policeman or firefighter shall thereupon cease to be liable to the provider for any charges for which liability has been assumed by the municipality, and the provider may not thereafter attempt to collect such charges from the policeman or firefighter, nor from the family or estate thereof.
     (b) With respect to any liability assumed by a municipality under subsection (a) of this Section, interest on the unpaid amount thereof shall begin to accrue 90 days after receipt of proof of claim by the municipality (or its agent or insurer if it so directs), at the rate established for judgments in the Code of Civil Procedure.
     (c) Pursuant to paragraphs (h) and (i) of Section 6 of Article VII of the Illinois Constitution, this Section specifically denies and limits the exercise by a home rule unit of any power which is inconsistent herewith, and all existing laws and ordinances which are inconsistent with this Section are hereby superseded. This Section does not preempt the concurrent exercise by home rule units of powers consistent herewith.