What is the name of your state? Or

I have a few questions concerning child support. Maybe someone can help me understand the system. The decree was signed approximately 1 1/2 years ago. In the decree my ex was given a pretty good size 'credit' for extraordinary travel expenses. (lives out of state) Now my ex, after only a year and a half has filed for a hearing to substancially reduce the child support obligation due to extraordinary travel expenses. Will a judge entertain such a reduction? I thought my ex would have to show a substancial change in circumstances to change the child support. Child support being paid now is well below state guidelines as it is. I am assuming my ex has found that moving so far away is costing more than initially anticipated, but should that be my problem?