In LA, "reimbursement of travel expenses" for employment IS used as income for child support purposes.
LOUISIANA REVISED STATUTES
TITLE 9. CIVIL CODE ANCILLARIES
CODE BOOK I--OF PERSONS
CODE TITLE V--DIVORCE
CHAPTER 1. DIVORCE
PART I-A. CHILD SUPPORT
SUBPART A. GUIDELINES FOR DETERMINATION OF CHILD SUPPORT
315. Definitions
As used in this Part:
(4) "Gross income" means:
(a) The income from any source, including but not limited to salaries, wages, commissions, bonuses, dividends, severance pay, pensions, interest, trust income, annuities, capital gains, social security benefits, worker's compensation benefits, unemployment insurance benefits, disability insurance benefits, and spousal support received from a preexisting spousal support obligation;
(b) Expense reimbursement or in-kind payments received by a parent in the course of employment, self-employment, or operation of a business, if the reimbursements or payments are significant and reduce the parent's personal living expenses. Such payments include but are not limited to a company car, free housing, or reimbursed meals; and
However:
(d) As used herein, "gross income" does not include:
(ii) Per diem allowances which are not subject to federal income taxation under the provisions of the Internal Revenue Code.
So, actually, if it is treated as expense reimbursement, it IS income. If it's REAL per diem, it's NOT treated as income.
I don't think, according to the IRS, it matters AT ALL what the per diem is actually used FOR. It either qualifies or it doesn't. (Though LdiJ should probably weigh in here).
First, let me clarify what "per diem" really is.
This insurance adjuster's case is a good example.
He is likely traveling around the country or a region, handling disasters. Its up to his employers to cover his costs while doing so (hotels, 1/2 of meals, incidentals etc.). This would not be taxable income nor should be included in a child support calculation.
An employer has a choice of covering each expense, individually, having the employee draw up an expense report, and then getting on the employee's butt if the employee chooses a hotel that is too expensive or spends too much on any one individual meal. The other choice is to pay the government, preset "per diem" for those expenses, which allows the employee to decide how much or how little to spend on each item. So, if the employee likes really fancy meals, they may decide to stay a the local roach motel to save money on hotels, and spend more of their per diem on fancy meals and drinks. Or in the alternative, the employee may prefer a comfortable hotel, and to eat from the dollar menu at fast food places. Sometimes an employee will choose to profit on the deal by both staying at the local roach motel AND eating from dollar menus. However, most of the time the preset per diem rates really just barely cover average expenses.
Based on what the OP has described, he has a traditional "per diem" situation, and that money should not be taxable or included in child support.
However, when employer paid expenses CAN and should be included in child support, is when the employer is providing housing, a car, or other items for the employee that actually reduce their living expenses. So, if an employee is, for example, a ranch hand who lives on the ranch and is provided housing, utilities and food, the value of those is normally added back to income in determining child support.
However, they are often NOT added back into income for tax purposes, because they are often considered to be "for the convenience of the employer" and in that situation its not a taxable benefit.
However...there CAN be per diem situations that are taxable, or should be taxable. We had one on here not too long ago that was clearly fraud on the employer's part, and technically on the employees part too.
A classic one is where the company gives a per diem rate that is higher than the "CONUS" rate (the government set rate). In those instances the per diem must be included on the W2 as wages, and then the employee gets to deduct actual employee business expenses on Schedule A via form 2106.
That is the one that gets tricky for child support purposes. For all intents and purposes the W2 show wages being much higher than they actually are. If this OP's per diem is going to be showing up on his W2 and he will have to deduct actual expenses, then he could have a problem. However, I suspect that is not the case because his per diem rate seems in line with CONUS for his region.