The Director of Finance shall have power to and shall be required to:
      A.    Prescribe the forms of receipts, vouchers, bills, claims, accounting forms and systems of accounts to be used by all the offices, departments and agencies of the City government;
      B.   Examine and approve the financial aspects of all contracts, orders and other documents by which the City government incurs financial obligations, having previously ascertained that sufficient moneys have been appropriated and allotted and will be available when the financial obligations shall become due and payable;
      C.   Audit and approve before payment all bills, invoices, payrolls and other evidences of claims, demands or charges against the City government and with the advice of the Department of Law, determine the regularity, legality and correctness of such claims, demands or charges;
      D.   Inspect and audit any accounts or records of financial transactions which may be maintained in any office, department or agency of the City government apart from or subsidiary to the accounts kept in his office.