Sec. 45. An administrative, a legislative, or other governmental body may not grant a zoning variance relating to the use of primary or secondary property without the prior approval of the commission upon the affirmative vote of at least six (6) members. The commission may approve the variance only if:
(1) the petition establishes by substantial evidence of probative value the correctness of the conclusions stated in section 47 of this chapter; and
(2) notices of the hearing have been given to all interested parties in the manner required by this chapter.