You seem to think that the judge will be stupid. You've established yourself as having an earning capacity of $25K per year, which isn't particularly impressive for an able-bodied adult of average intelligence, so you can expect that the court will expect you to be earning at least that amount. I was merely pointing out that your argument to the court, "It's not fair that I should be charged child support based on what I am capable of earning" is not going to fly, particularly when you're committing tax fraud - and can't or won't document your actual income because of that tax fraud.
You're choosing to engage in tax fraud, and that's likely to make it harder, not easier to avoid paying your support. Does that really surprise you?

