959Y Chargeable persons and other persons: assessment made or amended by Revenue officer.
(1) Subject to the provisions of this Chapter, a Revenue officer may at any time—
(a) make a Revenue assessment on a person for a chargeable period
>in such sum< as, according to the officer’s best judgment, ought to be charged on the person,
(b) amend a Revenue assessment on, or a self assessment in relation to, a person for a chargeable period in such manner as he or she considers necessary, notwithstanding that—
(i) tax may have been paid or repaid in respect of the assessment, or
(ii) the assessment may have been amended on a previous occasion or on previous occasions.
(2) For the purpose of making
>any assessment on< a chargeable person for a chargeable period or for the purpose of amending such an assessment, a Revenue officer—
(a) may accept either in whole or in part any statement or other particular contained in a return delivered by the chargeable person for that chargeable period, and
(b) may assess any amount of income, profits or gains or, as the case may be, chargeable gains, or allow any allowance, deduction, relief or tax credit by reference to such statement or particular.
(3) The amendment of an assessment by a Revenue officer does not preclude that Revenue officer or any other Revenue officer from further amending the assessment in such manner as he or she considers necessary.
(4) (a) Where any amount of income, profits or gains or, as the case may be, chargeable gains is omitted from, or not properly reflected in, an assessment for a chargeable period or the tax stated in an assessment is less than the tax payable by the chargeable person for the chargeable period, then a Revenue officer may make such amendments to the assessment as are necessary to ensure that the assessment includes the correct amount or to ensure that the tax stated in the assessment is equal to the tax payable by the chargeable person for the chargeable period.
(b) For the purposes of paragraph (a), the amendment of an assessment by a Revenue officer may include the addition of an amount of income, profits or gains or, as the case may be, chargeable gains that is not reflected in the assessment.