Talk:Empowered Frostbolt

I was wondering where the percentage that frostbolt normally gets came from. 81.4%. Did someone pull it out of thin air, or did I miss something somewhere? The base cast time for frostbolt is 3 seconds, which should make the percentage of +spell damage effect 100*3/3.5=85,71%. If the shortened casting time for frostbolt from talents is used, it's 100*2.5/3.5=71,43%. I don't know which one of these is used (I suspect the former), but neither gives me 81.4%. Before I go ahead and edit the page, can someone explain if I made a mistake?