Did she get the court's permission to move. If so she would have been warned that the original order stands until she meets residency requirements and then files to have the case moved to WA. If she didn't get the court's permission to move with the children, she has to come back to NC before a WA court will entertain any motion to move the case

You allowed your ex to relocate out of state w with the children wow. Anyways in answer to your question if the child support order is in your state now then your state holds juristiction, your ex can transfere the child support to her new state, however she cannot file against you for child support by her states laws until she becomes a resident if she has been there for six months she can try to file. Child support is determined by what you earn, so the amount you pay should not change, the only thing you would need to worry about is if both states require child support to be paid until your children reach the age of 18 and not 21. I just checked the child support age limit in both states and in washington child spport ends at the age of 18, unless administrative order and child is full-time expected to graduate before age 19, In Nc child support is to be paid until the child reaches the age of 18, unless secondary school full time up to the age of 20 whichever comes first. So actually for you child support in washington ends sooner than in NC so this could be a plus.

Why bcan someone keep changing how much child support I will pay? That doesn't seem right. The case should be closed thats what we agreed on and thats what I pay. This is ridculous!

If you are stating that you and the mother filed an agreemnt though the court for a set amount that you would pay for child support, this is common some parents do this although I did not get out of what you were asking that you and the mother had an agreement, if the agreement was not filed though the court and it was a verbal or notirized agreemnt then I can tell you that the courts do not aknowledge either, so neither would be legal and binding, and if you and the mother did file an agreement though the court, that agreement once the court granted it could not be modiflyed within a 2 year period from the date the judge signed the order after two years the custodial parent can file for an increase for child support.

Does she have to have a reason for needing an increase? And it was through the court.