An application for P-D District zoning shall be accompanied by a development schedule indicating to the best of the applicant's knowledge the approximate date when construction of the project can be expected to begin, the anticipated rate of development, and the completion date. The development schedule, if approved by the Commission, shall become part of the development plan and shall be adhered to by the owner of the property and successors in interest. Cash shall be deposited with the City or a savings and loan certificate or letter of credit or a performance bond issued by a corporate surety company, in an amount to be determined by the Director of Public Works, to cover the cost of public improvement adjacent to the proposed development prior to the issuance of the building permit for first-phase construction. The Planning Commission shall have authority to compare, from time to time, the actual development accomplished in the various P-D Zone Districts with the approved development schedules.