5(1)Where, by virtue of subsection (8) of the principal section, subsection (7) of that section has effect as if, in the prescribed accounting period, supplies of fuel for private use made in respect of two or more vehicles were made in respect of only one vehicle, the consideration appropriate shall be determined as follows—
(a)if each of the two or more vehicles falls within the same description of cubic capacity specified in Table A or Table B above, the Table in question shall apply as if only one of the vehicles were to be considered throughout the whole period; and
(b)if one of those vehicles falls within a description of cubic capacity specified in those Tables which is different from the other or others the consideration shall be the aggregate of the relevant fractions of the consideration appropriate for each description of vehicle under the Table in question.
(2)For the purposes of sub-paragraph (1)(b) above, the relevant fraction in relation to any vehicle is that which the part of the prescribed accounting period in which fuel for private use was supplied in respect of that vehicle bears to the whole of that period.