(Added by Ordinance No. 144762; amended by Ordinance Nos. 150375, 176003 and 181483, effective January 18, 2008.) The Workers' Compensation Self Insurance Operating Fund is hereby created as an internal service fund under the Office of Management and Finance described in Chapter 3.15 of this Code. Receipts of the Fund shall include service charges to user funds for administrative and legal expenses, insurance premiums, expected and unanticipated loss reserves, interest earned by the Fund and any other monies which are appropriate revenues. Expenditures from the Fund shall be made in accordance with appropriations made by the Council. Expenditures and encumbrances shall be limited to the balance in the Fund at the time and to purposes for which there is an appropriation or other source of reimbursement authorized at the time.