Mana song lower dps of the bard, so your dps may not even made up to it. That bard is too stubborn though, he should chose to play the song if your mana that low, even if he may not be agree with you dpsing ^^
On other hand, if you let your mana ever get that low, you were too focus in dpsing probably. Manage your mana better, and stop dps when it's not safe (meaning when you get in a group where ppl eat every single aoe xD )
