When a development plan, including the accompanying plans and surveys, is approved by the Board of Supervisors, said approval shall constitute an agreement by the applicant, developer or their heirs, successors or assigns that such development plan, including the erection of all buildings, structures and improvements, shall be completed and maintained as shown on the plan or plans submitted to the Township of Montgomery. If within three years of date of the approval of a development plan by the Board of Supervisors substantial construction of the proposed regional shopping center development is not undertaken by the applicant or developer in accordance with the approved plans, a new approval of the plan and the issuance of a new building permit or permits shall be required and obtained prior to the undertaking of any construction.