Anyone can explain the Skarner change from 5.5 patch Note?

Q - Crystal Slash DAMAGE 18/28/38/48/58 physical damage ⇒ 20/30/40/50/60 physical damage BONUS MAGIC DAMAGE 18/28/38/48/58 magic damage per stack of Crystal Energy ⇒ 20/30/40/50/60 magic damage per stack of Crystal Energy

So does it means if I have three stacks of Crystal Energy, I will do 20/30/40/50/60 x 3 bonus magic damage? If it does, it is not working now. If it does not, why you say per stack of Crystal Energy.