(a) Notwithstanding the provisions of Sections 20.5-28(d) and 29(d), if at the end of three (3) years from the date of approval of a preliminary plan a subdivider has not submitted a final subdivision plat, or has not diligently pursued approval of a submitted final plat, then the agent may, upon ninety (90) days written notice by certified mail to the subdivider, revoke the preliminary plan approval. Diligent pursuit of approval of the final subdivision plat shall mean that the subdivider has incurred extensive obligations and substantial expenses relating to the submitted final subdivsion plat or modifications thereto. The agent's written notice shall cite the specific facts upon which the revocation is based. In any event, when a final subdivision plat has been timely submitted but not approved the maximum term of validity for the associated preliminary plan shall be five years.

b) Following the expiration or revocation of any preliminary plat pursuant to subsection (a) above, any subdivision plan considered for the subject property shall be submitted and processed in accordance with all applicable procedures for new submissions.