Upon the closing of the polls, the judges shall count and canvass the votes for each office. At the conclusion of the canvass of votes on election night, the judges and clerks of the election shall sign the returns and file them with the business manager of the school district. However, if the election is held under an agreement with a city or county pursuant to sections 15.1-09-22 and 15.1-09-24, the returns must be canvassed and the winners declared as set out in the agreement.