Talk:Xerath/@comment-1920550-20150714115238/@comment-1920550-20150723211005

Simply because the  500 (+ 90% AP) is on a much bigger AOE, higher range and easier to land. Xerath has to use 3 shots on a main target (hopefully he can land single shots on more than one target), while Ziggs is a fire and forget in the middle of an entire enemy team. The point being that while Xerath's ult has more damage, Ziggs's ult damage ends up being more efficient due to the superior range until 16 and massive AOE.