Shawtay, I won't put this as an answer because I don't have any sources to confirm, but in my experience, it does not matter the amount of damage. There are many forms to participate during the boss fight and it is hard to make a fair formula. Also I saw some low levels drop rare items. I, myself, am level 96 and even though I can't do much, last night I got a wind-up key and the rest of my team (all level 200+) got nothing good.