In the case referred to in the preceding paragraph, if, after an Appropriation of the excess amount prescribed in that paragraph to the income tax to be collected upon the last payment of a specified public pension or retirement package in the year on or after December 1, 2025, there remains an excess amount that could not be fully covered by that Appropriation (or, if the excess amount includes any amount that has not yet been collected, the amount obtained by deducting the amount equivalent to the uncollected portion; referred to as the "overpaid amount" in this paragraph and the following paragraph), the payer prescribed in the preceding paragraph refunds the overpaid amount.