Powers of Board of Appeals on appeals. In exercising the powers described herein the Board of Appeals may, so long as such action is in conformity with the terms of this chapter, reverse or reaffirm, wholly or partly, or may modify the order, requirement decision or determination appealed from and may make such order, requirement decision or determination as ought to be made and, to that end, shall have the powers of the administrative official from whom the appeal is taken. The concurring vote for three members of the Board of Appeals shall be necessary to reverse any order, requirement, decision or determination of the administrative official or to decide in favor of the applicant on any matter upon which it is required to pass under this chapter or to effect any variation in the application of this chapter.