Obligation derived from law is not presumed. Obligation is a juridical necessity to give, to do and not to do. The Tax Code mandates that no other accounting shall be used for income taxation but the accounting bookkeeping in conformity with the Tax Code and the rules and regulation issued under its authority. The Tax Accounting rules can only be found from the letters of the laws and the interpretations made by the BIR Chief, the Court of Tax Appeals and the Philippine Supreme Court. Now, they are all available to you so that at the end, you become a law-abiding and obedient taxpayers. Don’t use PFRS, PSA, GAAP and GAAS for taxation purposes because they will give you headaches, heartaches and financial difficulty sooner than you think and expected.