At the 30,000 foot level only. Usually, they are concretely set by a court at fixed dollar amounts, and you must petition the court based on changed circumstances to get them altered. OP reports doing so and failing. It may be the right thing at that point would have been to appeal that ruling (but appeals are not necessarily cheap), especially if the state has a strong objective rule that the decision did not comport with (some do, and rogue judges are a thing, especially when they have animus against a party, which “the party is a sex offender” might easily explain.)
He might just have to struggle with being in arrears for a few years if the current agreement was issued recently.
Learn the law in your state, figure out what forms you need to fill out yourself. I believe you file motions "pro se".
If you say you're as good as you are, figuring this stuff out for you should be easy, I understand the funk you're in.. but as you can see.. there are complete strangers rooting for you, and your family. Sometimes you just need to see things from a different perspective.