What is the standard of proof required for assessing a loss of income before a loss is determined?

In Gao v. Dietrich, 2018 BCCA 372 at paras. 39–40, our Court of Appeal provides guidance on the applicable standard of proof when assessing this loss:

The rationale for distinct standards of proof for past actual events and past hypothetical events was explained by Madam Justice Rowles in Smith v. Knudsen, 2004 BCCA 613 at para. 29: … What would have happened in the past but for the injury is no more “knowable” than what will happen in the future and therefore it is appropriate to assess the likelihood of hypothetical and future events rather than applying the balance of probabilities test that is applied with respect to past actual events.