“In the case of Ramsay v. Ramsay, 1999 CanLII 15027 (ON SC), [1999] O.J. No. 4835, Aston J. stated, at paragraph 10:
[…] the “presumption” [in sub rule 24(1)] that success determines entitlement to costs does not mean that a successful party is always entitled to costs, unless that party has “behaved unreasonably” as contemplated under sub-rule 24(4). In my view, the court’s discretion under section 131 of the Courts of Justice Act is wider than that and still allows for consideration of the factors expressed by Katarynych J. in Beaumont v. Fransden, supra. There may be an increased emphasis on the outcome or “success” as a factor, but the fact that success is only presumptive under Rule 24(1) invites consideration of other factors. Otherwise, Rule 24(1) would simply read “A successful party is entitled to costs”.
This passage from Ramsay was endorsed by the Court of Appeal in M. (C.A.) v. M (D.), at paragraph 41.
In M. (C.A.) v. M (D.) the Court of Appeal confirmed, at paragraphs 40 – 42, that:
a) although the Family Law Rules have circumscribed the broad discretion granted by section 131(1) of the Courts of Justice Act they have not completely removed the trial judge’s discretion;
b) although the general provision, sub rule 24(1), enacts a “presumption” that the successful party is entitled to costs of the case, it does not require that the successful party is always entitled to costs;
c) a successful party may not obtain a costs award in his or her favour even in circumstances not falling within sub rule 24(4);
d) there may be circumstances aside from the unreasonableness of the successful party’s conduct that rebut the presumption; and
e) the financial situation of the parties can be taken into account in setting the amount of the costs award either under Rule 24 or Rule 18 pursuant to the direction in sub rule 24(11) that the court take into account “any other relevant matter”.”