never if possible go in arrears, you cant wiave them, nor can a court, retroactively decrease support in arrears, but she can if she wanted. The downside to youre income decreasing is the fact that these jackals dont care, and in most state plans are required to put you in at a potental level regaurdless if you can go there again or not, however the reason behind youre decrease, pending whether or not it was intentional might favor ok, but rarely will it. A person has to know how to fight it correctly and lawfully and there is no way or alloted space to explain it to you short of just saying you can try, as far as her tax returns, or non applicateing income you better have some substantial proof to what you say or they want care, and cash is hard to proof.