What is the test for retroactive maintenance when a payor falsified their income so that their income was lower than the original payor's?

The Court then observed: However, it should be noted that these "exceptional circumstances" referred to in Wilkinson are required only when an order of retroactivity is sought which encompasses the time period preceding the filing of the initial application. For example, in Wilkinson, the custodial parent sought a variation of maintenance that was to extend back over the entire period of time between the date of the original order and the date of the variation order. In that circumstance, the blameworthiness of the payor and diligence on the part of the payee are relevant and the rule makes good sense. It is based on the proposition that there is a presumption that a previous court order is to be respected [see: Willick v. Willick, 1994 CanLII 28 (SCC), [1994] 3 S.C.R. 670]. However, if the payor falsified his or her income so as to achieve a lower amount of maintenance payable, or if the payee sat for years and took no action, it seems clear that in the former situation, a retroactive order would be appropriate, while with the latter, a retroactive order would be very unfair to the payor spouse.