Second round interview on campus?

I go to a target and had a 1st round interview with BB through OCR yesterday. People at MD and VP level came to campus and conducted 1st round interview for like 20 students in the morning. In the afternoon, they called me up and told me they were doing 2nd round on campus if I were available. I attended, and there were only 3 of us for the second round. It was a slightly longer interview than the first one and asked me at the end where I got interviews so far. Is this usual? I didn't ask if it was the second round in order to get the superday or it was just replacing superday.