All skilled and intermediate care nursing facilities licensed by the Department of Health and Environmental Control shall be required to furnish an item-by-item billing for all charges to the patient or the person paying such bill, upon request by such patient or person. Items which remain unpaid are not required to be itemized again. Such requests for itemized billing shall remain in effect until further notification by the patient or person paying such bill. Provided, that the provision herein shall not apply to the contracted amount of a state or federal agency. Any amount above such contract shall be itemized as provided herein.