What is the test for a temporary change to a final court order?

Similarly, in Psaila v. Sandurska, 2020 ONSC 4291, McDermot J. stated, at para. 10: However, more is required in the case of a temporary change to a final court order and lengthy status quo. This is partly because the court is usually addressing this issue through untested and unreliable affidavit evidence that is often conflicting, and impossible to reconcile. As well, the final arrangement sought to be changed is also presumed to be reflective of what the parties thought the best interests of the children were at the time that the agreement was struck.