Treatment of autism spectrum disorder through applied behavior analysis shall be covered under the medical assistance program under this Article for children with a diagnosis of autism spectrum disorder when (1) ordered by a physician licensed to practice medicine in all its branches or a psychologist licensed by the Department of Financial and Professional Regulation and (2) evaluated by a behavior analyst as recognized by the Department or licensed by the Department of Financial and Professional Regulation to practice applied behavior analysis in this State. Such coverage may be limited to age ranges based on evidence-based best practices. Appropriate State plan amendments as well as rules regarding provision of services and providers will be submitted by September 1, 2019. Pursuant to the flexibilities allowed by the federal Centers for Medicare and Medicaid Services to Illinois under the Medical Assistance Program, the Department shall enroll and reimburse qualified staff to perform applied behavior analysis services in advance of Illinois licensure activities performed by the Department of Financial and Professional Regulation. These services shall be covered if they are provided in a home or community setting or in an office-based setting. The Department may conduct annual on-site reviews of the services authorized under this Section. Provider enrollment shall occur no later than September 1, 2023.