The final plat shall conform substantially to the preliminary plat as approved, and, if desired by the subdivider, may constitute only that portion of the approved preliminary plat which he proposes to record and develop at the time; provided, however, that such portion conforms to all requirements of the regulations set forth in this chapter. Subsequent final plats covering the remaining portions of the preliminary plat shall be submitted within 24 months of the date of approval of the preliminary plat.