(1) If you have a * decreasing adjustment relating to a supply made by you through an agent or made to you through an agent, an obligation under subsection 29-75(2) to issue an * adjustment note for the adjustment, or an obligation under subsection 134-20(2) to issue a * third party adjustment note for the adjustment:
(a) arises whether the * recipient makes a request for an adjustment note or a third party adjustment note to you or the agent; and
(b) is complied with if either you or your agent gives the recipient an adjustment note or a third party adjustment note within 28 days after the request.
(2) However, you and the agent must not both issue separate * adjustment notes or * third party adjustment notes for the adjustment.
(3) This section has effect despite sections 29-75 (which is about adjustment notes) and 134-20 (which is about third party adjustment notes).