Relevant provision of law: "The Commission (on Audit) shall have exclusive authority, subject to the limitations in this Article, to define the scope of its audit and examination, establish the techniques and methods required therefor, and promulgate accounting and auditing rules and regulations, including those for the prevention and disallowance of irregular, unnecessary, excessive, extravagant, or unconscionable expenditures, or uses of government funds and properties." (Art. IX-D. Sec. 2(2), Philippine Constitution)