Territory which is annexed to the Village shall automatically be classified to the highest restrictive use under the then existing Village zoning ordinance, unless the person or persons petitioning for annexation are requesting a zoning use other than the highest restrictive use, then in that case, a plan for zoning the area to be annexed shall be forwarded to the Village Board by the Plan Commission. Upon approval of such plan for zoning the area to be annexed, the Village Board shall direct the Village Plan Commission to hold a public hearing in accordance with the regulations of chapter 15 of this title. (1979 Code § 5-2-3)