(1) Subject to section 19, a liability is a registrable maintenance liability if:
(a) it is a liability of a person (the payer ) to pay an amount to another person (the payee ); and
(b) it arises under a court order made under section 143 of the Assessment Act; and
(i) under paragraph 143(1)(a) of that Act in overturning on appeal a declaration under section 106A of that Act, or in response to a declaration under section 107 of that Act that the payee should not be assessed in respect of the costs of the child, because the payee is not a parent of the child; or
(ii) under paragraph 143(1)(b).
(2) Subsection (1) does not apply to the extent that a
liability to pay an amount is a liability to pay any costs incurred in respect
of proceedings instituted under section 143 of the Assessment Act.