What is the burden of proof against a party who claims business expenses to reduce their income for child support purposes?

[64] In the case of Favero v. Favero, 2013 ONSC 4216, 2013 CarswellOnt 8414, Chappel J noted at paragraph 103: 103. Where a party raises questions regarding the reasonableness of business expenses, the burden of proof is on that party to establish that the expenses are unreasonable. There is a distinction between this onus and the onus on the party claiming the deductions to establish their income. The parent who relies on expenses to reduce their income cannot simply put forth numbers for alleged business expenses with no justification or evidence to support those numbers, and then put the other party to the expense of disclosure motions and questioning in an effort to obtain proof regarding the specifics and actual amounts of the expenses. Rather, that party has an obligation to explain the reasons for the expenses and how they were calculated, and must provide documentary proof of the expenses in an organized manner so that the court can make a proper determination as to the reasonableness of the expense from the standpoint of the child support calculation. This is particularly important in situations where the expenses reported on the party's income tax returns fluctuate from year to year. If the party fails to provide meaningful supporting documentation or other evidence in respect of those deductions, an adverse inference may be drawn by the court in making the income determination.