Why Is Our Child Support Being Evaluated

I live in Kansas and my husband pays child support for his 11 year old son. He recently received a letter from an attorney for the State of Kansas asking him to fill out a Domestic Relations Affidavit so they can evaluate his child support to see if any modifications are necessary. He called his ex to see if she requested the child support to be modified and she said no and that they had sent one to her as well. She marked on her copy that she did not want the support adjusted at this time. My question is, why is the state evaluating their child support if they have not requested it. Also, if it would have been adjusted would the state have taken it to court or would we each have to hire our own attorneys?