No action or decision of the Board shall be valid or binding unless a majority of all the members concur therein; provided, however, where required by law or this article, no action or decision shall be valid or binding in the absence of a two-thirds or unanimous vote. Roll call votes, when taken, shall commence with the closest member to the left of the presiding officer and shall continue clockwise, the presiding officer voting last. (Rule 12, Ord. 555, as amended by § 2, Ord. 1227, eff. November 5, 1998)