It can make perfect sense when you see it through the eyes of the person/enity doing the garishment. The problem I see is that a change in the court order for support between the parents is not binding on the person/entity that is doing the garnishment. The garnishment order it received earlier is binding on that person/entity. What the person/entity doing the garnishment gets concerned about if stops the garnishment without an order directed to the person/entity doing the garnishment is that it may then be subject to sanctions for violating the court that ordered it to do the garnshment. On the other hand, if it gets an order specifically directing it to stop the garnishment it doesn't run that risk. In other words, it's a CYA policy that informed businesspersons/entites use to be sure it won't be the one left having to pay for the order out of its own pocket.