64(1)The appellant may apply to HMRC for a determination if the appellant has grounds to believe that—
(a)a person has been overcharged to multinational top-up tax;
(b)an amount of tax postponed under a previous determination is excessive or insufficient.
(2)An application must be made within 30 days after the specified date (see paragraph 55(4)), unless sub-paragraph (3) applies.
(3)This sub-paragraph applies if—
(a)there is a change in the circumstances of the case as a result of which the appellant has grounds to believe the matter in sub-paragraph (1), or
(b)the application could, if it were a notice of appeal, be given at a later date under paragraph 55(6).
(4)The application must state the amount believed to be overcharged and the grounds for that belief.
(5)HMRC may determine—
(a)whether any amount of tax is to be postponed, and
(b)the amount of any tax postponed.
(6)The amount of any tax postponed is to be determined as the amount (if any) by which it appears that there are reasonable grounds for believing that the person is overcharged.