Section 56National Internal Revenue Code of 1997 (Republic Act No. 8424), Sec. 56

Payment and Assessment of Income Tax for Individuals and Corporation. -

(A) Payment of Tax. -

(1) In General. - The total amount of tax imposed by this Title shall be paid by the person subject thereto at the time the return is filed. In the case of tramp vessels, the shipping agents and/or the husbanding agents, and in their absence, the captains thereof are required to file the return herein provided and pay the tax due thereon before their departure. Upon failure of the said agents or captains to file the return and pay the tax, the Bureau of Customs is hereby authorized to hold the vessel and prevent its departure until proof of payment of the tax is presented or a sufficient bond is filed to answer for the tax due.

(2) Installment of Payment. - When the tax due is in excess of Two thousand pesos (P2,000), the taxpayer other than a corporation may elect to pay the tax in two (2) equal installments in which case, the first installment shall be paid at the time the return is filed and the second installment, on or before July 15 following the close of the calendar year. If any installment is not paid on or before the date fixed for its payment, the whole amount of the tax unpaid becomes due and payable, together with the delinquency penalties.

(3) Payment of Capital Gains Tax. - The total amount of tax imposed and prescribed under Section 24 (c), 24(D), 27(E)(2), 28(A)(8)(c) and 28(B)(5)(c) shall be paid on the date the return prescribed therefor is filed by the person liable thereto: Provided, That if the seller submits proof of his intention to avail himself of the benefit of exemption of capital gains under existing special laws, no such payments shall be required : Provided, further, That in case of failure to qualify for exemption under such special laws and implementing rules and regulations, the tax due on the gains realized from the original transaction shall immediately become due and payable, subject to the penalties prescribed under applicable provisions of this Code: Provided, finally, That if the seller, having paid the tax, submits such proof of intent within six (6) months from the registration of the document transferring the real property, he shall be entitled to a refund of such tax upon verification of his compliance with the requirements for such exemption.

"In case the taxpayer elects and is qualified to report the gain by installments under Section 49 of this Code, the tax due from each installment payment shall be paid within (30) days from the receipt of such payments.

No registration of any document transferring real property shall be effected by the Register of Deeds unless the Commissioner or his duly authorized representative has certified that such transfer has been reported, and the tax herein imposed, if any, has been paid.

(B) Assessment and Payment of Deficiency Tax. - After the return is filed, the Commissioner shall examine it and assess the correct amount of the tax. The tax or deficiency income tax so discovered shall be paid upon notice and demand from the Commissioner.

As used in this Chapter, in respect of a tax imposed by this Title, the term 'deficiency' means:

(1) The amount by which the tax imposed by this Title exceeds the amount shown as the tax by the taxpayer upon his return; but the amount so shown on the return shall be increased by the amounts previously assessed (or collected without assessment) as a deficiency, and decreased by the amount previously abated, credited, returned or otherwise repaid in respect of such tax; or

(2) If no amount is shown as the tax by the taxpayer upon this return, or if no return is made by the taxpayer, then the amount by which the tax exceeds the amounts previously assessed (or collected without assessment) as a deficiency; but such amounts previously assessed or collected without assessment shall first be decreased by the amounts previously abated, credited returned or otherwise repaid in respect of such tax.