Irrespective of the source of funds, any school district whose budget of total expenditures, including debt service, exceeds seventy-five million dollars annually is subject to the provisions of Chapter 35, Title 11, and shall notify the Director of the Office of General Services of the Budget and Control Board of its expenditures within ninety days after the close of its fiscal year. However, if a district has its own procurement code which is, in the written opinion of the Office of General Services of the State Budget and Control Board, substantially similar to the provisions of the South Carolina Consolidated Procurement Code, the district is exempt from the provisions of the South Carolina Consolidated Procurement Code except for a procurement audit which must be performed every three years by an audit firm approved by the Office of General Services. Costs associated with the internal review and audits are the responsibility of the school district and will be paid to the entity performing the audit.