Should the board allow damage, or should the court on appeal allow damage to the claimant as provided for in section 31-919, additional assessments of benefits shall be made against the lot and land owners by supplemental assessments upon the proportion fixed by the original assessment upon the lots and lands benefited to pay such claim, to be certified and collected as original assessments. Should this additional amount to be so assessed be less than five hundred dollars the board in its discretion may pay the same from the drainage fund created by section 31-905.