Originally Posted by morteriag

On a boss, using ABarr is time not spent building up your AB stack, and with todays spellcofficient it will result in a loss in dps. However, in situations where you dealing with targets that will die within seconds, it might be usefull to use ABarr after Mbarr, since you might not have time to cast AB. Note that ABarr have a flighttime aswell, so it might not hit your target in time, even though it is instant.