"CHAPTER III - PROTESTING AN ASSESSMENT, REFUND, ETC.

"SECTION 228. Protesting of Assessment. - When the Commissioner or his duly authorized representative finds that proper taxes should be assessed, he shall first notify the taxpayer of his findings: Provided, however, That a preassessment notice shall not be required in the following cases:

"(a) When the finding for any deficiency tax is the result of mathematical error in the computation of the tax as appearing on the face of the return; or

"(b) When a discrepancy has been determined between the tax withheld and the amount actually remitted by the withholding agent; or

"(c) When a taxpayer who opted to claim a refund or tax credit of excess creditable withholding tax for a taxable period was determined to have carried over and automatically applied the same amount claimed against the estimated tax liabilities for the taxable quarter or quarters of the succeeding taxable year; or

"(d) When the excise tax due on excisable articles has not been paid; or

"(e) When an article locally purchased or imported by an exempt person, such as, but not limited to, vehicles, capital equipment, machineries and spare parts, has been sold, traded or transferred to non-exempt persons.

"The taxpayers shall be informed in writing of the law and the facts on which the assessment is made; otherwise, the assessment shall be void.

"Within a period to be prescribed by implementing rules and regulations, the taxpayer shall be required to respond to said notice. If the taxpayer fails to respond, the Commissioner or his duly authorized representative shall issue an assessment based on his findings.

"Such assessment may be protested administratively by filing a request for reconsideration or reinvestigation within thirty (30) days from receipt of the assessment in such form and manner as may be prescribed by implementing rules and regulations. Within sixty (60) days from filing of the protest, all relevant supporting documents shall have been submitted; otherwise, the assessment shall become final.

"If the protest is denied in whole or in part, or is not acted upon within one hundred eighty (180) days from submission of documents, the taxpayer adversely affected by the decision or inaction may appeal to the Court of Tax Appeals within thirty (30) days from receipt of the said decision, or from the lapse of the one hundred eighty (180)-day period; otherwise, the decision shall become final, executory and demandable.