17. The amount of an appropriate authority’s community charge benefit subsidy for the relevant year—
(a)for the purposes of section 31F(2) of the Act (subsidy in respect of community charge benefit) shall be the amount or total of the amounts calculated in accordance with article 18;
(b)for the purposes of section 31F(5) of the Act (subsidy in respect of the costs of administering community charge benefits) may include an additional sum in respect of the costs of administering community charge benefits calculated in accordance with Schedule 2.