“The Supreme Court of Canada stated the following in Michel v. Graydon, 2020 SCC 24, commencing at para. 10:
[10] In D.B.S., this Court endorsed certain important principles governing orders for child support (including retroactive child support) that merit restating here:
– Child support is the right of the child, which right cannot be bargained away by the parents, and survives the breakdown of the relationship of the child’s parents (para. 38);
– Child support should, as much as possible, provide children with the same standard of living they enjoyed when their parents were together (para. 38);
– The child support owed will vary based upon the income of the payor parent, and is not confined to furnishing the “necessities of life” (paras. 38‑45).
– Retroactive awards are not truly “retroactive”, since they merely hold payors to the legal obligation they always had to pay support commensurate with their income (para. 2);
– Retroactive awards are not confined to “exceptional circumstances” or “rare cases” (para. 5); and
– In determining whether to make a retroactive award, the payor parent’s interest in certainty in his/her obligations must be balanced with the need for “fairness and . . . flexibility”. A court should consider whether the recipient parent’s delay in seeking retroactive support was reasonable in the circumstances, the conduct of the payor parent, the circumstances of the child, and the hardship the retroactive award might entail (para. 133).
The Supreme Court went on to state at para 32:
[32] Retroactive child support awards will commonly be appropriate where payor parents fail to disclose increases in their income. Again, D.B.S. is instructive: “a payor parent who knowingly avoids or diminishes his/her support obligation to his/her children should not be allowed to profit from such conduct” (para. 107). And where the strategy for avoiding child support obligations takes the form of inadequate or delayed disclosure of income, the effect on the child support regime is especially pernicious. This is because the methodology adopted by the Federal Child Support Guidelines, SOR/97‑175, which are expressly incorporated in the FLA, results in information asymmetry. Apart from shared parenting arrangements, the Guidelines calculate child support payments solely from the payor parent’s income. At any given point in time, therefore, the payor parent has the information required to determine the appropriate amount of child support owing, while the recipient parent may not. Quite simply, the payor parent is the one who holds the cards. While an application‑based regime places responsibility on both parents in relation to child support (D.B.S., at para. 56), the practical reality is that, without adequate disclosure, the recipient parent will not be well‑positioned to marshall the case for variation.
…
The Supreme Court stated in Colucci v. Colucci, 2021 SCC 24, stated commencing at para. 4:
[4] The applicable framework must give effect to the objectives and provisions of the Federal Child Support Guidelines, SOR/97-175 (“Guidelines”), particularly the core objective of safeguarding the child’s right to a “fair standard of support” (s. 1). Retroactive variation applications also require courts to weigh the certainty and predictability provided by an existing court order against the need for flexibility in a system that ties support to fluctuating payor income. The framework set out below balances these interests in a way that incentivizes payment of the right amount of child support when it is due and the timely disclosure of financial information — the linchpin of a just and effective family law system. Rules which create perverse incentives to ignore or postpone parental support obligations are to be firmly rejected in favour of legal standards designed with the fundamental purposes of child support in mind.
In Colucci, para. 34 the Supreme Court went on to state:
[34] The enactment of the Guidelines in 1997 marked a paradigm shift in Canadian child support law away from a need-based approach to one which clearly established the child’s entitlement to support commensurate with the payor’s income (D.B.S., at paras. 42-45). The Guidelines rest on the principle that “spouses have a joint financial obligation to maintain the children of the marriage in accordance with their relative abilities to contribute to the performance of that obligation” (Divorce Act, s. 26.1(2)). Section 3 of the Guidelines provides that the amount of child support is presumptively determined in accordance with the applicable table in Schedule I. Putting aside shared custody arrangements, the tables generally allow parents and courts to calculate the amount of child support owing based on just two numbers: the payor’s income, and the number of children to be supported…”