I just had my interview there too and the new format isn't a big deal. Really, it almost felt like you didn't have enough time with each interviewer. All three interviewers were very friendly and most of their questions were oriented towards getting to know me better and expanding on things in my applications. It really was less formal and scripted than other interviews I've had, though it might depend on who you get.
You of course cover some of the same ground with each interviewer, but it gives you three chances to get it right. The interim dean explained to us that the intention is to provide more data points (he is a biostatistician after all!) and give us a better chance to let them know what we're about rather than rely on a single impression from one session.
(This is Chris for those that were there with me yesterday). Good luck everyone!
PS: For those still interested, I submitted my supplemental August 16th and received my interview offer September 12th.