If there are no obligations outstanding which are secured by an interim project assessment, the board may, at any time and without notice or hearing, order that the uncalled balance of such interim project assessment be canceled and that the amount of the credit against the original assessment represented by such uncalled balance of said interim project assessment be annulled for each tract of land in the district. In such event, notwithstanding the provisions of Section 46379, the amount of said original assessment to be collected from each tract of land in the district shall be increased by the amount of the credit that was so annulled; provided, however, said amount

shall be decreased by the amount of any payment made on the uncalled balance of said interim project assessment. Interest due on the recomputed collectible amount of said original assessment shall be computed as provided in Section 46671 or 47303 as the case may be.