On or before August 31 of each fiscal year, the Board shall, in accordance with this section, determine the amount of the reduction, if any that will have to be made in the following fiscal year in the amount of the windfall benefit components of persons entitled to such benefit components under the Railroad Retirement Act. A reduction must be made where it is determined that the balance in the Dual Benefits Payments Account, comprised of such funds as will be available for the payment of windfall benefits in the following fiscal year including the enacted or estimated appropriation to the Account for the next succeeding fiscal year, disregarding any interest which may be earned by the moneys in the Account during the next fiscal year, is less than the estimate of the amount of the windfall benefits that would be payable under the Railroad Retirement Act during such fiscal year if no reduction were to be applicable. The amount of the windfall benefit as determined by the Board and paid to a person under this section shall constitute full and complete payment of the person's windfall component and there shall be no further liability on the part of the Board, the U.S. Government, or any other person or entity for the amount of any reduction imposed.