Heroic Harjatan, Frost DK in Blood DK dps ranking

Was looking through logs and notice this one blood dk who was ahead of everyone by 200-300k dps on heroic Harjatan. Being a veteran blood dk player, I knew it was impossible to get numbers those high unless they can down the boss in less than a minute, which was not the case and so I looked into that player and found out, he wasn’t even a blood dk, but a frost dk. For whatever reason, logs put him down as blood instead of frost or he did some kind of exploit but that’s unlikely