The City Council shall provide for an independent biannual audit of all City accounts and may provide for more frequent audits as it deems necessary. Such audits shall be made by a certified public accountant or firm of such accountants who have no personal interest, direct or indirect, in the fiscal affairs of the City government or any of its officers. The Council may, without requiring competitive bids, designate such accountant or firm annually or for a period not exceeding two years, but the designation for any particular fiscal year shall be made no later than 30 days after the beginning of such fiscal year. If the state auditor general makes such an audit, the Council may accept it as satisfying the requirements of this section.