hello212
looks like someone on the previous page did some number crunching and found that ≤10% of people with 720+ GMAT and 3.5+ GPA were dinged w/o interview @wharton.
That said, this is my take on the slew of invites that come out on the last day. Applications are reviewed by ~2 AdCom's and if they are in agreement about interview (this is apparently how another school does it and it makes sense), that individual gets invited immediately. If divided, then Dir of Admission (Ankur Kumar in this case) has a last look at the individual applications and might decide to go ahead with the interview anyway or ding. Several interviews support this sequence of events.
It may just be my wishful thinking, since I was told by admission that they were reviewing my application on the 10th of Feb (when I sent in a significant update on my startup). Unlikely that they would take 2 weeks to 'review' my appl. So, of all the wild hypothesis that are swimming in my head every thursday evening, this one makes the most sense.