Any change order authorized under this Section shall be made in writing. Any person employed by and authorized by any unit of State or local government to approve a change order to any public contract who knowingly grants that approval without first obtaining from the unit of State or local government on whose behalf the contract was signed, or from a designee authorized by that unit of State or local government, a determination in writing that (1) the circumstances said to necessitate the change in performance were not reasonably foreseeable at the time the contract was signed, or (2) the change is germane to the original contract as signed, or (3) the change order is in the best interest of the unit of State or local government and authorized by law, commits a Class 4 felony. The written determination and the written change order resulting from that determination shall be preserved in the contract’s file which shall be open to the public for inspection. This Section shall only apply to a change order or series of change orders which authorize or necessitate an increase or decrease in either the cost of a public contract by a total of $25,000 or more or the time of completion by a total of 180 days or more.