25.     Tax period

            (1) Subject to subsection (2), the tax period applicable to a registered person under this Act is the period of one month ending on the last day of each month.

            (2) The Minister may, by regulations, authorise a different tax period for specific categories or classes of registered persons.

26.     Returns

            (1) Every registered person shall furnish the Commissioner General with a return for each tax period, within 25 days after the end of the period whether or not tax is payable in respect of that period.

            (2) A return shall be in the prescribed form, and shall-

     (a)     state the information necessary to calculate the tax payable in accordance with section 19 for the period; and

     (b)     be furnished in the manner prescribed.

            (3) In addition to any return required under this Act, the Commissioner General may by notice in writing require any person, whether or not a registered person, to furnish the Commissioner General, whether on that person's own behalf or as agent or trustee of another person, with such further or other return in the prescribed form and when required by the Commissioner General for the purposes of this Act.

            (4) A person who fails to furnish a return as required by this Act, commits an offence and is liable on conviction, to a fine not exceeding P5,000 or to imprisonment for a term not exceeding one year, or to both.

            (5) Where a person convicted of an offence under subsection (4) fails to furnish the return within a further period specified by the Commissioner General by notice in writing, that person commits an offence and is liable on conviction to a further fine of P50 for each day during which the failure continues and to imprisonment for three months without the option of a fine in lieu of imprisonment.

            (6) A person who fails to furnish a return within the time required under this Act is liable to a penalty which is the greater of:

     (a)     P50 per day for each day or part thereof that the return remains outstanding; or

     (b)     an amount equal to 10 per cent of the tax payable for the period of such return for each month or part thereof that the return remains outstanding.

            (7) The penalty imposed under subsection (6) shall not exceed the amount of tax payable in respect of the return or import declaration.

            (8) A person dissatisfied with a decision of the Commissioner General under subsection (3) may appeal against the decision only in accordance with the provisions of Part VIII.

27.     Extension of time

            (1) Upon application in writing by a person, the Commissioner General may, where good cause is shown by the person, extend the period within which a return required under section 26 is to be furnished.

            (2) The granting of an extension of time under subsection (1) does not alter the due date for payment of tax under section 33.

            (3) A person dissatisfied with a decision of the Commissioner General under subsection (1) may appeal against the decision only in accordance with the provisions of Part VIII.

28.     Assessments

            (1) Where-

     (a)     a person fails to furnish a return as required by section 26 or fails to furnish an import declaration as required by section 15(1) or (2);

     (b)     the Commissioner General is not satisfied with a return or import declaration furnished by a person;

     (c)     the Commissioner General has reason to believe that a person has become liable for the payment of an amount of tax but has not paid such amount;

     (d)     a person, other than a registered person, supplies goods or services and represents that tax is charged on the supply;

     (e)     a registered person supplies goods or services and the supply is not a taxable supply or is a taxable supply charged with tax at the rate of zero percent and, in either case, the registered person represents that a positive rate of tax is charged on the supply; or

     (f)      the Commissioner General has determined the liability of any person in terms of section 71(2),

          the Commissioner General may make an assessment of the amount of tax payable by the person or of the amount of tax represented by the person as payable in respect of a supply.

            (2) The person assessed under subsection (1)-

     (a)     in the case of an assessment under subsection (1)(d) or (e), is the person making the supply; or

     (b)     in the case of an assessment under subsection (1)(f), is the person whose liability has been determined under section 71(2); or

     (c)     in any other case, is the person required to account for the tax under this Act.

            (3) An assessment under subsection (1)(a), (c), (d), (e), or (f) may be made at any time.

            (4) An assessment under subsection (1)(b) may be made-

     (a)     at any time, where the default was due to-

           (i)       fraud; or

          (ii)       gross or wilful neglect committed by, or on behalf of, the person who furnished the return or import declaration; or

     (b)     in any other case, five years after the date the return or import declaration was furnished.

            (5) The Commissioner General may, based on the information available, estimate the tax payable by a person for the purposes of making an assessment under subsection (1).

            (6) Where an assessment has been made under this section, the Commissioner General shall serve a notice of the assessment on the person assessed, which notice shall state-

     (a)     the tax payable;

     (b)     the date the tax is due and payable; and

     (c)     the time, place, and manner of objecting to the assessment.

            (7) The Commissioner General may, within three years after service of the notice of assessment, amend an assessment by making such alterations or additions to the assessment as the Commissioner General considers necessary, and the Commissioner General shall serve notice of the amended assessment on the person assessed.

            (8) An amended assessment is treated in all respects as an assessment under this Act.

            (9) An amount assessed under subsection (1)(d), (e) or (f) shall be treated, for all purposes of this Act, as tax charged under this Act.

29.     General provisions relating to assessments

            (1) The production of a notice of assessment or a certified copy of a notice of assessment is receivable in any proceedings as conclusive evidence that the assessment has been duly made and, except in proceedings under Part VIII relating to the assessment, that the amount and all particulars of the assessment are correct.

            (2) No assessment or other document purporting to be made, issued, or executed under this Act shall be-

     (a)     quashed or deemed to be void or voidable for want of form; or

     (b)     affected by reason of mistake, defect, or omission therein, if it is, in substance and effect, in conformity with this Act and the person assessed, or intended to be assessed or affected by the document is designated in it according to common understanding.