If the Zoning Board of Adjustment lacks a quorum because any of its regular or alternate members is prohibited by the MLUL from acting on a matter due to the member's personal or financial interest therein, Class IV members of the Planning Board shall be called upon to serve, for that matter only, as temporary members of the Zoning Board of Adjustment. The Class IV members of the Planning Board shall be called upon to serve, in order of seniority of continuous service to the Planning Board, until there are the minimum numbers of members necessary to conform to the MLUL, to act upon the matter without any personal or financial interest therein, whether direct or indirect. If a choice has to be made between Class IV members of equal seniority, the Chairman of the Planning Board shall make the choice.