10.—(1) Before the start of each obligation period identified in the first column of Schedule 1 (except the first such period), the Secretary of State is to add the estimate referred to in article 6(1) for that period and the estimate referred to in article 7(1) for that period.
(2) The figure representing the sum of those estimates, multiplied by 0.2, is calculation C for that obligation period.
(3) Where calculation C is not a whole number, it is to be rounded to the nearest whole number (one-half being rounded upwards).
(4) References to calculation C in articles 11 and 12 are to be construed accordingly.