In Nebraska, you send payments through the court system, called 'friend of the court'. So all my regular payments went that way. BTW I used to make them with a credit card so I earned flight miles at least. Anyhow, if I needed or wanted to send the kids money for xmas, bday, any occasion or need I would send it to the court and notify the ex and kids it was coming that way. Worked well for a long time and built up a nice credit. Like so many others, my regular payments never seemed to find their way to the kids needs but ended up benefiting my ex whom I affectionately called '#$%* dog'.
So if you have auto deduction, you might consider changing if they take a credit card and get a card that pays off in miles. good for a lot of free plane tickets. Also, check with them on sending any extra in to them as well, they track it all and you should be able to log online and check your balance, I did to make sure I was getting credit. The ex never knew about that. Just as long as she got her regular allotment every month she was none the wiser.