MSN is correct. Here's the full schedule for OZ 978:

Leave DEN 1005, arrive ALO 1244 (Snack)
Leave ALO 1256, arrive MSN 1330
Leave MSN 1341, arrive RFD 1407
Leave RFD 1418, arrive ORD 1445

What's interesting about OZ's schedule at MSN is that the schedules for the two flights to MKE were 2123-2150 and 2238-2305. The return flights were scheduled as 0615-0638 and 0705-0730. The 0615 flight continued to STL, and the 0705 continued to SUX and DEN. I don't think there were many people wanting to take a 2238 flight from MSN to MKE, so I'm guessing OZ had a line maintenance base in MKE and these flights were operated for maintenance reasons, not for passenger convenience.