Each college and university shall be audited as provided by board policy. The policy shall be designed to ensure financial integrity, necessary internal controls, and appropriate accordance between board policies and campus expenditures. The college or university may arrange for any additional audits it desires by contracting with the legislative auditor or a private certified public accountant. Nothing in this section shall limit the authority of the legislative auditor to perform selected scope audits or other duties of the office as provided under section 3.971.