Opening bills, closing bills, monthly bills rendered for periods of less than the days set by resolution, and other bills requiring proration, will be computed in accordance with the applicable schedule, but the amount of the fixed charge or minimum charge specified therein, will be prorated on the basis of the ratio of the number of days in the period to the number of days in the average billing period. Should the total period of service be less than one month no proration will be made and no bill shall be less than the specified monthly fixed charge or minimum charge. (Ord. 1940 NCS §2 (part), 1993; Ord. 544 NCS §5; prior code §27.49.)