29.—(1) Paragraph (2) applies if—
(a)relevant payments are normally made to an employee at regular intervals of a week or more, and
(b)the employee’s code is used on the non-cumulative basis.
(2) If the relevant payment is the second or subsequent relevant payment made to the employee during the payment period (as defined by regulation 25(6)), the amount of tax to be deducted must be—
(a)calculated by reference to the aggregate of the relevant payments made to the employee during the payment period (as defined by regulation 25(6)),
(b)increased by any tax not deducted because of the overriding limit when the previous relevant payment in that payment period was made to the employee, and
(c)reduced by the amount of tax calculated when the employer made the previous relevant payment in that payment period.
(3) But, for the purposes of the aggregate, any effects of regulation 30(2) (regular payments treated as made at later date) must be disregarded.
(4) Paragraph (5) applies if relevant payments to an employee—
(a)are normally made at regular intervals of less than a week, or
(b)are made at irregular intervals of less than a week.
(5) If the relevant payment is the second or subsequent relevant payment made to the employee during a tax week, the amount of tax to be deducted must be—
(a)calculated by reference to the aggregate of the relevant payments made to the employee in the tax week,
(b)increased by any tax not deducted because of the overriding limit when the previous relevant payment in that tax week was made to the employee, and
(c)reduced by the amount of tax calculated when the employer made the previous relevant payment in that tax week.