When computing alimony do you use "reported" IRS income?

In the case of McQuaig v. McQuaig, 36 So.3d 801 (Fla. 1st DCA 2010), the court found:  

TRIAL COURT DID NOT ERR IN REFUSING TO REDUCE HUSBAND'S INCOME FOR CERTAIN CLAIMED "BUSINESS EXPENSES"; THE FACT THAT HUSBAND CAN DEDUCT EXPENSES FOR TAX PURPOSES DOES NOT MAKE THEM "ORDINARY AND NECESSARY" FOR CHAPTER 61 INCOME CALCULATION PURPOSES.

The Husband sought a modification of alimony based on his asserted decrease in income. The court ultimately reduced the alimony from $8,000 per month to $5,000 (on a temporary basis for two years) and further ordered the Husband to pay $8,500 toward the $17,200 attorney's fees incurred by the Wife during the modification proceedings. On appeal, the Husband contended that the trial court erred by failing to deduct business expenses when computing his income, specifically, that the trial court was required to deduct his "ordinary and necessary business expenses" in calculating his gross income. The District Court held:

1. "In 2008, the Former Husband earned $119,949 from his distributorship…. On his 2008 tax return, he deducted $30,028 in business expenses for an unadjusted gross taxable income of $89,921. The deducted expenses included: car and truck expenses; office expenses; repairs and maintenance; travel; deductible meals and entertainment; and 'other expenses' (telephone, internet/phone/fax; software; passport; clothing; freight; [publications]; entertainment; parking)." 

2. "Citing section 61.30, Florida Statutes, and cases interpreting that statute, the Former Husband argues the trial court was required to deduct his 'ordinary and necessary' business expenses in calculating his gross income. The statute he relies on governs child support determinations and provides that in determining a parent's monthly income for that purpose, gross income includes 'business income,' which in turn 'means gross receipts minus ordinary and necessary expenses required to produce income.'"

3. "We are not persuaded section 61.30 should be applied in this case where the relevant statute is section 61.08 governing alimony awards, and that statute speaks only in terms of 'financial resources' and 'all sources of income.' But even assuming the definition of 'business income' in section 61.30 is properly applied here, the trial court did not act unreasonably in declining to accept the Former Husband's representations. Except for a $500 monthly car allowance the Former Husband received as a sales representative, there is no evidence in the record showing he incurs expenses in selling surgical equipment as a distributor that differ from those he incurred as a salesman or that previously were paid or reimbursed by his former employer. That the Former Husband can now deduct those expenses for tax purposes does not make them ipso facto 'ordinary and necessary' for Chapter 61 income calculation purposes and he has presented no authority - nor have we found any - to support such a proposition."

4. "Absent such authority or any competent, substantial evidence of what expenses are 'ordinary and necessary' to running the Former Husband's distributorship, the trial court did not abuse its discretion in finding that his 2008 gross income was $120,000."