any class of hereditaments to which paragraph (c) of article 9 applies, in any year beginning on or after 1st April 1991,

any class of hereditament the rateable value of which falls in pursuance of article 11(3) or 13(3) to be determined in accordance with the standard formula, in any year beginning on or after 1st April 1992, and

any class of hereditaments to which article 12 or 14 applies, in any year beginning after an intermediate year, the rateable value of that class in such a year shall be the amount produced by calculating in respect of that year in accordance with the standard formula.