Section 305 ILCS 5/5C-3 - Payment of assessment; penalty(a) The assessment imposed by Section 5C-2 for a State fiscal year shall be due and payable in quarterly installments, each equalling one-fourth of the assessment for the year, on September 30, December 31, March 31, and May 31 of the year.(b) The Illinois Department is authorized to establish delayed payment schedules for care providers for persons with a developmental disability that are unable to make installment payments when due under this Section due to financial difficulties, as determined by the Illinois Department.(c) If a care provider for persons with a developmental disability fails to pay the full amount of an installment when due (including any extensions granted under subsection (b)), there shall, unless waived by the Illinois Department for reasonable cause, be added to the assessment imposed by Section 5C-2 for the State fiscal year a penalty assessment equal to the lesser of (i) 5% of the amount of the installment not paid on or before the due date plus 5% of the portion thereof remaining unpaid on the last day of each month thereafter or (ii) 100% of the installment amount not paid on or before the due date. For purposes of this subsection, payments will be credited first to unpaid installment amounts (rather than to penalty or interest), beginning with the most delinquent installments. Amended by P.A. 099-0143,§ 640, eff. 7/27/2015.