If the director determines that an allowance under the Medicare program is not reasonable or if a medical treatment, accommodation, product, or service existing as of June 29, 1995, is not covered under the Medicare program, the director, at any time, may establish an additional fee schedule or schedules not exceeding the prevalent charge for fees for services actually received by providers of health care services, to cover charges for that treatment, accommodation, product, or service. If no prevalent charge for a fee for service has been established for a given service or procedure, the director shall adopt a reasonable rate which shall be the same for all providers of health care services to be paid for that service or procedure.