In all cases which are not appealed to the district court within the prescribed time, the decision of the board of tax appeals shall be conclusive and all records shall be corrected to comply with the decision of the board. A final decision or order of the board of tax appeals directing a market value change for taxable property that is not further appealed shall be fixed for the current year appealed and there shall be no increase in value for the subsequent assessment year when no physical change occurs to the property; provided however, that annual trending or equalization applied to all properties of a property class or category within the county or a clearly defined area shall still apply. If the order requires repayment or refund of taxes these shall be repaid or refunded by the proper authorities and, if the order affirms or establishes a liability for the payment of taxes, the usual procedure for collection of such taxes shall continue or commence.