(A)   If upon final inspection of an excavation or fill it is found that the work authorized by the grading permit has been satisfactorily completed in accordance with the requirements of this subchapter and any other requirements imposed, a grading certificate covering such work, and stating that the work is approved, shall be issued to the permit holder by the City Engineer.
   (B)   The City Engineer shall have the power to revoke any grading certificate whenever he or she finds that the work covered by the certificate has been materially extended or altered, without a permit to do so, or that any retaining walls, cribbing drainage structures, fence or other protective device shown on the approved plans and specifications submitted with the application for a permit have not been maintained in good order and repair. Before the revocation, the City Engineer shall first give written notice to the permit holder and to the owner of the property involved, specifying the defective condition and stating that unless such defective condition is remedied satisfactorily, within a specified time, the grading certificate may be revoked. If the defective condition is remedied, the certificate shall not be revoked.
(`94 Code, § 151.23)