(1) An approved project plan or preliminary project plan shall be in effect for all SDP zones within two (2) years after the approval of an SDP Overlay zone. If a project plan has not been approved within two (2) years after a Specific Development Plan Overlay zone has been applied to a specific property, the Planning Commission shall initiate a rezoning action to revert such property to the zone existing thereon prior to the establishment of the SDP zone.

(2) If an approved project plan or preliminary project plan expires, a rezoning action to revert said zone shall be initiated.