18.—(1) Where a contract includes the provision of orthodontic services, the contract must specify the number of units of orthodontic activity to be provided by the contractor—
(a)where the contract begins on 1 April, in each financial year; or
(b)where the contract begins on a date other than 1 April, in the remainder of the financial year in which the contract begins, and in each financial year thereafter.
(2) Where paragraph (1) applies, the contract must also contain terms which have the effect of those provisions specified in Part 2 of Schedule 2 in relation to the calculation of the number of units of orthodontic activity that the contractor will provide under the contract.