What is the test for determining costs in a child protection case when the judge has not presided at all or any stage of the proceeding?

[42] In the Children’s Aid Society of Toronto v. L.L.,[10] Spence J. projected the difficulty of determining the responsibility for costs in a case when the judge had not presided at each step of the proceeding as follows: … [A] family could be engaged in this kind of lengthy litigation, appear in court many times, before different judges, over a period of several years and never once raise the issue of costs until the last day of the final court appearance. At that time, the family should then be permitted to say, in effect: “Judge, we want you to go back over this litigation for the past five years, reconstruct all the proceedings notwithstanding you are not the judge who presided at all (or any) appearances and make a decision based upon all the considerations set out in Rule 24 as to which party, if anyone, should be entitled to costs and what the quantum of those costs should be. To put the proposition thus is to reveal its inherent unworkability. Such a task would be beyond daunting for a court; it would be next to impossible…