Can a father who is self employed use the fact that he is making…

I guess you meant residence in terms of your home.

If he does have a change of income that is a legitimate material change in circumstance. That means it's enough to get the Court to consider a variation. Then he has to prove his lower income.

If new information has come to light that proves you misrepresented something the Court would consider that as a change as well. If nothing new has come up this is not an appeal and it will not matter.

His lowered standard of living may be a material change in circumstance and may be considered if he wants to take the position that he is suffering from undue hardship. In that case the Court would consider both of your standards of living.

A material change in circumstance may also be that the kids have reached adulthood. He doesn't seem to raise that but the fact that their needs may be less could come in there.

The table amount doesn't necessarily apply to adult children. But, they would only be required to provide some of their income to help with school expenses.

A change of circumstances could be that they no longer have the same special expenses.

The fact is that he and you should be contributing to their school expenses and the kids will be expected to pay something.

This will be a messy. He's going to show much less income and this is going to be your biggest area of concern. At the same time if they don't take soccer etc he won't have to provide for that but will for school.

I hope that helps.