What is the test for variation of maintenance orders?

The case to which the trial judge was undoubtedly referring is Willick v. Willick 1994 CanLII 28 (SCC), [1994] 3 S.C.R. 670 which sets out the following test for variation of maintenance orders: In deciding whether the conditions for variation exist, it is common ground that the change must be a material change of circumstances. This means a change, such that, if known at the time, would likely have resulted in different terms. The corollary to this is that the matter which is relied on as constituting a change was known at the relevant time, it cannot be relied on as the basis for variation.