it's very common to get rejected from lower ranked schools but get accepted to higher ranked ones. there are many reasons, sometimes lower ranked schools have high selectivity due to small class sizes (Yale and Haas come to mind). sometimes, school don't perceive you as a good fit for the school. sometimes, adcom might be having a bad day. who knows?
last year, jb32 got rejected from every top 20 school he applied except McCombs and Kellogg.
the take away is not to put all your eggs in one basket, especially when it comes to b-school. there's too many variables to be predictable.