4.—(1) If the specified year is a year in which local lists must be compiled (“the revaluation year”), the amount to be calculated for the purposes of paragraph 1(1)(b) in relation to the authority for the year in respect of the area is that described in sub-paragraph (2).
(2) That amount is the amount calculated in accordance with the formula—
where—
N is the amount calculated in accordance with paragraph 3(2) or 3(3), as the case may be, for the preceding year;
P is the aggregate rateable values shown in the relevant billing authority’s local list for 1st April in the revaluation year for the hereditaments, other than those hereditaments to which paragraph 2(2) applies, falling within the designated area;
Q is the aggregate rateable values shown in the relevant billing authority’s local list for 31st March in the preceding year for the hereditaments, other than those hereditaments to which paragraph 2(2) applies, falling within the designated area;
R2 is the small business non-domestic rating multiplier for the revaluation year;
R1 is the small business non-domestic rating multiplier for the preceding year.
(3) For the purposes of this paragraph, the rateable value of a hereditament shown in the relevant billing authority’s local list for 31st March in the preceding year is to be taken to be the rateable value that would have been shown in that list for that day had the circumstances relating to that hereditament been as they were on 1st April in the revaluation year.