A client or, in the case of a child, the child or the child’s parent may be required to pay a fee for mental health services provided under sections 245.461 to 245.486 and 245.487 to 245.4889. The fee must be based on the person‘s ability to pay according to the fee schedule adopted by the county board. In adopting the fee schedule for mental health services, the county board may adopt the fee schedule provided by the commissioner or adopt a fee schedule recommended by the county board and approved by the commissioner. Agencies or individuals under contract with a county board to provide mental health services under sections 245.461 to 245.486 and 245.487 to 245.4889 must not charge clients whose mental health services are paid wholly or in part from public funds fees which exceed the county board’s adopted fee schedule. This section does not apply to regional treatment center fees, which are governed by sections 246.50 to 246.55.