[giantg2]

Yeah, I've heard of similar things in the US. I think it requires going to court to have the amount reduced or eliminated. I think it usually requires that the change in occupation be involuntarily (like being fired or laid off) so that people can't game the system that way.

And sometimes the system fails the other direction too. My wife's father got divorced and had a high paying job, so he was required to pay a lot of child support. He was in a car accident which resulted in him being in a coma for months. Since he wasn't making money during that time in the hospital, his bank account was emptied and the court issued an arrest warrant since the child support was not being paid. He lost his job and was never able to get a new one. He's now living on food stamps and waiting to reach the social security age. The family court system ruined his life.