Ill. Admin. Code tit. 56, § 2920.25
e) The fact that the period of announced shutdown for vacation or inventory purposes covered under this Section is preceded or followed by a layoff due to lack of work or a period of vacation or holiday covered under Sections 2920.30 or 2920.35 does not affect the treatment of the payments received under this Section. The existence of the situations described in subsections (d) and (e) might be relevant evidence, however, in deciding whether the announced shutdown was truly for vacation or inventory purposes under subsection (c).