After audit of the revenues and expenses of a public transportation system, or through the use of certified financial statements, as required by section 975.6, if the commissioner determines that the revenues, as defined in section 975.4 (c) of this Part, exceed the expenses, as defined in section 975.4 (d) of this Part, the transportation system must submit a plan to dispose of the surplus funds by maintaining or reducing fares or maintaining or increasing services. The transportation system shall submit the plan within 30 days of receiving the order in such form as may be prescribed by the Commissioner. Upon approval, the plan shall be implemented as soon as practical. Upon the failure of the transportation system to submit or implement a plan, the surplus shall be used to reduce the proportionate shares of the State and the county, municipality or Indian tribe required to make matching payments to the transportation system or, in the event that no future payments are to be made to the transportation system, the surplus funds shall be proportionately refunded to the State and the county, municipality or Indian tribe involved.