They were incredibly open about the whole process, the scoring, the ranking, etc.
Basically, they think their yield is going up and they don't want to overfill the class. Historically, the classes size has been 8 students: see their website for the student roster. It's taken more than 16 offers to fill it, though the yield was better last year according to our info session. This year they will take 11 or 12. They speculated that it would take 24 offers but they would be pleasantly surprised if they could fill the class in 20 offers. They were clear these were just off the cuff remark and the actual committee would deliberate on exactly how to do it. So you're looking at somewhere between a 30% and 40% chance if you interviewed.