Payments by local authorities to water authorities
4. Subject to article 7 below, the Perth and Kinross Council shall pay—
(a)to the North Authority a sum calculated in accordance with the formula in article 3(1) above, but for the purposes of that calculation the area of that Council shall be treated as if it did not include the first added area;
(b)to the East Authority a sum calculated in accordance with the formula in article 3(1) above, but for the purposes of that calculation the area of that Council shall be treated as if it consisted only of the first added area.