3. The amount of an authority’s housing benefit subsidy for the relevant year—
(a)for the purposes of section 30(2) of the Act (subsidy in respect of rebates or allowances) shall be the amount or total of the amounts calculated in accordance with article 4;
(b)for the purposes of section 30(3) of he Act (subsidy in respect of the costs of administering housing benefit) may include an additional sum in respect of the cost of administering housing benefit calculated in accordance with Schedule 1.