The "official" interview that occurred at SLE this past summer was a very unofficial "official" interview. Basically, at the end of the week, the squad leader came in and asked a few questions (5 or 6 at the most) - he/she made some notes and then went on to the next person. Our squad leader interviewed all 12 of us in less than 45 minutes.
The interview I had with my LO was much more official. He interviewed me over a long lunch (probably 2 hours), asked me tons of questions, and gave me tips for the application.
In the end, I think both interview notes were sent to USMA Admissions.