(1) This section applies if:
(a) the Secretary pays an amount to, or in relation to, a person for a child by way of an instalment; and
(b) the amount exceeds the amount that should have been paid to, or in relation to, the person under Part 3 - 3.
Note: Instalments may stop being payable with retrospective effect if the payability determination is set aside or varied after the instalments are paid.
(2) An amount equal to the amount of the excess is a debt due to the Commonwealth by the person.
(3) The debt under subsection (2) arises when the Secretary pays the amount mentioned in paragraph (1)(a).