The “waivers” granted to Iowa, New Hampshire, and South Carolina in November 2007 were very different from the waivers sought by Michigan and Florida.
The DNC, as far back as August 2006, granted waivers to Iowa, New Hampshire, Nevada, and South Carolina to hold pre-Super Tuesday primaries and caucuses in 2008. The DNC at that time set tentative dates for each of the four contests.
New Hampshire, Iowa, and South Carolina ended up deviating from those tentative dates, and thus needed a second waiver in November 2007. Florida and Michigan committed the more egregious violation of moving from the post-Super Tuesday period to the forbidden pre-Super Tuesday period. In fact, it was Florida’s action which precipitated the Iowa and New Hampshire rescheduling, since NH state law specifies that its primary be held a week earlier than any other state primary. South Carolina also moved its primary, from 1/29 to 1/26 in order to hold it on a weekend.
So Iowa, NH, and SC were granted technical waivers for movement within the pre-Super Tuesday period, but MI and FL were denied substantive waivers for barging into the pre-Super Tuesday period uninvited.