Child support amounts which are less than the state guidelines by more than $10 are referred to as deviated child support orders. Deviated child support orders do not automatically end when a child turns 18 years of age. To change or terminate a deviated child support order, you must file a Petition to Modify.
Child support amounts greater than the state guidelines comply with the guidelines. Your judge will almost always approve an amount greater than the guidelines. Even though Utah law states that child support amount greater than the guidelines comply with the guidelines, you must still file a petition to modify to terminate or change this higher amount.
Caution:
If you file a petition to modify an amount of child support which is greater or lesser than the guideline amount you will have to have a "substantial and material change in circumstances" before the judge will grant the modification. What this means is that a judge will not lower or raise the child support amount merely because a parent's income has changed. Instead, the judge will want to know why the income has changed, whether or not the change is permanent, and most importantly, has the ability of the parent to earn permanently changed.
Note that this differs significantly from the methods and criteria for changing amounts within the guidelines under Utah Code 78B-12-210 which allows a review after three years and an automatic modification if income has changed by 10% or more. Section 78B-12-210 also allows modification sooner than three years if income has changed by 30% or more. In short, if your final order has an amount greater or lesser than the guidelines, you may be stuck with that amount even if the income of one of the parents changes. Modifying deviated child support is sigificantly more difficult than modifying guideline child support.
Note also, even though both of you stipulate to an amount of child support which deviates from the state guidelines, your judge may still choose to order a guideline amount.
If your judge is willing to order the deviated amount which you have stipulated to, the judge must make a specific finding that the state guideline amount is unjust, inappropriate, or not in the best interest of your child(ren).