depends
Sorry to hear about your situation.
What state are you in?
you need a great lawyer .. . .
dont skimp and most of all - shop around . .
I went through two before I found what I needed . . and it cost me a bunch!
Ask lawyers whom they would go to if they were going through a nasty divorce with child custody issues . . just because someone is good at divorce doesn't mean they know shizzen about custody@!
I went through mine in NC, my initial attorney for the child support was state appointed through child support services (I was an FO and qualified for food stamps). he had no clue . . .so I shopped out someone recommended as a good overall family lawyer . . .she sucked and had no clue about a complex custody case nor child support law on that level . . good basic attorney but no idea how nasty folks get.
I asked for a continuance when my x wife wanted everything left and anything coming in after she had already soaked me in 60,000 in credit cards and loans without my knowledge and my kid's college fund.
I spent two days at the court house watching attorneys that were recommended . . . how they interacted with the judges, their peers and vice versa.
I picked the one with the brass ovaries that carried herself with poise and a big ole stick when needed!
Cost me 5 grand to retain, 750 to do the child support and and another 15 over the next 10 years to finally get custody in a state that does not give custody to men - esp airline pilots! . . worth every penny!
My first attorney had no clue how to relate the per diem, the real attorney understood how to relate it using the tax return as the basis for presenting the funds as non income . . you need that detail and that understanding that it is not income . . it is a reimbursement for money already spent and no where near what the actual CONUS is . . .so you are constantly on the loosing side of the equation!
get a good lawyer that Understands the law and your job or spend a lot of time prepping to explain how it works when you go in to see him.
Either way . . . dont skimp . . you get what you pay for - folks dont pay above market rate for mediocrity!