The Value Added Tax (Flat-rate Valuation of Supplies of Fuel for Private Use) Order 2013

3.  Step 2 – calculating the prospective excise duty differences

If a change in the rate of excise duty liable to be charged on road fuel is due in the period beginning on the date that the Commissioners revalorise the amounts in the base valuation table and ending a calendar year after the next revalorisation start date the prospective increase or decrease in the amount of excise duty chargeable per litre of each of the fuels is to be calculated by—

(a) adding the amount of VAT that is applicable to the increased or decreased amount of excise duty chargeable and rounding down the resultant figures to the nearest whole penny,

(b) dividing the number of days of the calendar year beginning on the revalorisation start date in which the increase or decrease in excise duty is likely to apply by 365 (or 366 in a leap year) and expressing the result of that calculation as a percentage rounded down to two decimal places, and

(c) multiplying the increased or decreased amount calculated in accordance with sub-paragraph (a) in respect of each of the fuels by the percentage calculated in accordance with sub-paragraph (b), each resultant figure is to be rounded down to the nearest whole penny.

If the valuation table is intended to have effect for less than a full calendar year the periods specified in sub-paragraph (b) above must be amended accordingly.