(1) A court having jurisdiction under this Part must not, at any time, make, revive or vary a child maintenance order in relation to a child on the application of a person (the applicant ) against, or in favour of, a person (the respondent ) if an application could properly be made, at that time, by the applicant under the Child Support (Assessment) Act 1989 for the respondent to be assessed in respect of the costs of the child, or vice versa.
(2) Subsection (1) has effect whether or not an application for administrative assessment of child support for the child has in fact been made (whether by the applicant, the respondent or another person).
(3) This section does not apply to proceedings under regulations made for the purposes of section 110 or 111A.