Modification or adjustment of child support obligation must be based on change in circumstances.

1. Except as otherwise authorized by law or this chapter, after a court has established a child support obligation, any subsequent modification or adjustment of the child support obligation must be based upon a change in circumstances. 2. The receipt of public assistance by a child or an obligee constitutes a change in circumstances that will allow the review and, if appropriate, modification of the child support obligation in accordance with the child support guidelines in effect at the time of the review. 3. The adoption of or any revision to this chapter must not, in and of itself, be considered a change in circumstances sufficient to justify the modification of any existing order or money judgment.