Motion to deviate from child support guidelines

My ex was going to file a motion to deviate from child support guidelines during the time that child support was set up 2 years ago; however, it was dismissed. However, he had not turned in his severance pay information at that time which I am in the process of filing a motion to compel discovery to get the back support. I am just getting prepared in case he tries to file the motion to deviate from CS guidelines. Would a judge even consider deviating since he has failed to disclose “all” of his income anyway (in addition to hiding all of his real estate income which would be hard to prove)? What are the usual reasons a judge would allow a deviation?

The court may deviate from the guidelines upon motion of either party and a finding that an application of the guidelines would not meet, or would exceed the child’s reasonable needs.

Would the decision to deviate be based on all circumstances or just reasonable needs of the child. My ex is hiding income and just bought a 3/4 million dollar home to live in. Can I present that recent purchase as evidence of his economic status? (His income is still less than $300,000 annually, which the CS guidelines are based on presently; he is disclosing only early retirement income now). Also, my pay has decreased over the last several years since a conversion to new automated medical system. I was able to find a company that still uses the old system and the pay is a little better now, but all the medical companies may switch to the automated version and pay cuts will be by approximately one-third over the next 4 years. Would these factors be considered? Is it basically just up to the judge presiding?

I am probably overthinking all this but just want to be prepared for anything that is going to come up in court. Thanks so much for all your help!

It is based on the reasonable needs of the child and the relative ability of each parent to provide support. You may attempt to show the judge evidence of his recent property purchase if it goes to show he is concealing income.