No, the Illinois statute governing Child Support is 750 ILCS 5/505 and it provides statutory minimum guidelines for support. In Illinois, divorces and family law related matters (child support/custody) are done by a judge. It is possible to ask for a deviation of child support (either up or down) depending upon the circumstances. You should also be aware that the Illinois Supreme Court recently amended the rules regarding how family law cases are handled in every court. There are time limits for custody trials and certain procedures which must be followed -- ie mediation; and parenting classes. Child Support deviation cases can be quite difficult and driven by various case law as well as the particular fact pattern. Consult an attorney in your area who is familiar with family law and your particular judges.
I believe the response Attorney Kevin Lee Linder provided is 99.9% correct. The exception to this rule would be a child support withholding case filed against an employer for failing to withhold or failing to turnover funds that were withheld. This type of action could be heard in front of the judge handling the child support case previously or as a separate case at law. A case filed in the law division could be heard in front of a jury in most Illinois counties.