That sounds pretty insane to me.

IME (hiring, not interviewing) it's always been 3-4 rounds. First is an HR phone screen (usually 20-30 minutes on the phone), 2nd with hiring manager, 3rd with a senior engineer/architect, and a 4th with the hiring VP. And those are almost always combined into a single morning or afternoon(2+3 or 3+4) and the final round doesn't always happen (VP's choice).