“My husband and his ex-wife both agreed to a child support amount, was written up and all legal. She recently served him with papers that she wanted more money than he was paying, and wants to get back child support over and above what she had agreed on. We reside in Tennessee, please let me know if this is legal, or once an agreement is made how can she back up now and say she wants more?”
In many states, a support order can be modified to the presumptively correct amount (in California we call it guideline support) any time it can be shown that circumstances have changed such that the child is either being over or under supported. So even though they made an agreement before, if the amount of support is no longer the correct amount, the Court has the ability to change that order to the correct amount. For the most part, absent some sort of fraud, she will not be able to modify support for a time period prior to when she filed her papers.