(a) The liability shall be the amount listed in Appendixes A and B based on the adjusted family income.
(b) If the liability amount listed in Appendixes A or B—nonresidential services or residential and short-term inpatient services—exceeds 12.5% of the total monthly family income, the liability shall be 12.5% of the total monthly income. Total monthly family income shall be determined on an annualized basis.
(c) The amount billed may not exceed the actual cost of the service provided.