The Director of Public Service shall, as soon as practicable after any excavation has been made in any street, thoroughfare, park or public ground, restore the pavement or other surfacing thereof, unless he shall authorize such restoration to be made by the person making the excavation. When such pavement or other surfacing is restored to his satisfaction he shall determine the restoration cost to the City, including the cost of all such inspections, of all backfilling done by the City, of all labor and material expended in repairing or resurfacing, and a reasonable charge for overhead services. The Director shall certify such cost to the City Auditor, who shall thereupon issue a receiving warrant or voucher, to transfer to the General Fund so much of the deposit made in respect of such improvement as may be necessary to defray the cost so certified, and shall return any balance in such deposit to the depositor. If the cost so certified exceeds the amount deposited, the City Auditor shall proceed forthwith to collect the remainder due the City. However, in lieu of the deposit required by Section 901.03 and the procedure provided in this section, the applicant for the permit may deposit the sum of five hundred dollars ($500.00) in cash with the Director of Public Service and shall not thereafter, for so long as such cash sum is left on deposit, be required to make the deposit called for in Section 901.03, provided that upon the restoration of the pavement or other surfacing and upon being billed for the cost as stipulated in this section, the applicant shall pay to the City the cost, as certified by the Director, and shall continue to pay upon being billed for each successive opening thereafter.