craven's posts make a lot of sense. I recently spoke to a few classmates about the offer process after callbacks, and they figured there will be more "late" offers this year because of the new NALP rules about having to make a decision 45 days or so after the offer.
While the offers might start "rolling out" in mid-September, I can see a second round of offers going out in early October. While some of these early October offers might appear to be offers that just happen to come later in the recruiting schedule, they are in fact, "re-offers."
*shrugs shoulders*