4If, when the needs element for any year falls to be paid, it appears to the Secretary of State that the aggregate amount of that element will exceed or fall short of its aggregate amount as fixed by the relevant rate support grant order, the Secretary of State shall adjust the amount of that element payable to each local authority as nearly as may be in the proportion which the aggregate amount of the element as so fixed bears to the amount, as estimated by the Secretary of State, which would be the aggregate amount of that element for that year apart from this paragraph.