It's a vote of no-confidence from Moos. Basically, Moos is saying "I would have fired you this past season except you miraculously rattled off 22 wins."
It sucks that we're basically going to waste another year treading water. But if the Frost hire is anything to go on, I trust Moos to get a good coach after this plays out.
And hey, if Miles gets a great assistant, keeps his team mostly intact and closes a good recruiting class, plus competes well in the Big Ten next year, maybe he gets a real extension this time next year.