Is it usual to have a team of people interview someone, rather than a lot of one-on-one or two-on-one sessions? This reduces the number of developer-hours used in interviewing. I don't think that adding a 3rd or more interviewer will add anything, and it can be intimidating for candidates, adding noise to your search for a suitable one.
In a couple of decades of occasional job interviews, I've done mostly 1:1 and a handful of 2:1.
I've only done one 4:1, which was actually lunch in between all-day 1:1 interviews, and which didn't feature any technical questions just random social conversation. It was definitely still part of the interview, though.
