A governmental unit may choose not to increase its total of restricted funds by the full amount allowed by law in a particular year. In such cases, the governmental unit may carry forward to future budget years the amount of unused restricted funds authority. The governmental unit shall calculate its unused restricted funds authority and submit an accounting of such amount with the budget documents for that year. Such unused restricted funds authority may then be used in later years for increases in the total of restricted funds allowed by law. Any unused budget authority existing on April 8, 1998, by reason of any prior law may be used for increases in restricted funds authority.