(1) The Commissioner-General may, by notice in writing, specify that an instalment payer or class of instalment payers is not required to submit an estimate under section 122.

(2) Where an instalment payer is not required to submit an estimate by reason of subsection (1), the Commissioner-General shall

(a) make an estimate of the estimated tax payable by that person for the year of assessment, which may be based on the tax payable for the previous year of assessment with an upward adjustment; and

(b) serve on the instalment payer a written notice stating the estimate of the Commissioner-General and the manner in which the estimate is calculated.

(3) For the purposes of section 121, where the Commissioner-General serves a notice under subsection (2), the estimated tax payable by the person for the year of assessment is the amount estimated by the Commissioner-General.