What is the test for a change of income under s. 17 of the Divorce Act?

The relevant question before the chambers judge was whether the appellant’s means, needs and circumstances on March 30, 2010, were actually changed sufficiently to bring into focus both the terms of s. 17(4.1) of the Divorce Act, and the terms of the divorce judgment. In our view, the settlement agreement, when it referred to change of income as a basis to return to court, was not intended to alter the usual law and to substitute a mechanical test. The relevant question before this court is whether the chambers judge reasonably and lawfully exercised his discretion to decline to grant the relief sought: Brill v. Brill, [2010] A.J. No. 846 (QL), 2010 ABCA 229 (CanLII) at para. 24.