To be fair, Seed Bearers have a short timer, so it's understandable that people would want to kill it quickly. Didn't know about the damage not counting until all teams finished though, that's a neat trick.

I have my last team slot set to one member specifically for raid bosses. This isn't particularly for the benefit of other members though. Working full time means I have less breathing room to complete the daily raid boss quest, so it makes sense for me to quickly hit the same raid boss three times to get progress for the quest.