So I guess this is the point where I out myself as being one of Michael's lowly, badly paid part-time associates. My store is advertising the new section too but we've yet to clear out any current yarn. From what I've heard from one of my managers, it will still carry the usual stuff, but just more new selections of yarn.
The next time I go to work, I'll ask what's the deal with the new store brand yarn. Be warned though that no other staff there that I know of knows anything about knitting or yarn so they may not be able to give me a helpful answer.