depends on padding i guess. if it does increase your single target dps for example havoc: immo, 2xinci + rof on 2 targets on maegera then its pretty much beneficial for the raid. if on the other hand you abuse havoc for shadowburn on this fight (not mentioning chaos bolts as some hero might pop up and say that he is doing that for soul leech shields) then its pointless and you are just gimping your raid grp.
but if you have the boss on farm and you can basically do whatever you want then who cares..