I have not done the calculations but I only know that its cost is too cheap, all the people are using the same OP skill in Cyrodiil killing entire parties.
Hey, i've just level'd up my vampirism to 6 and got Bat swarm. Skill calculators show that it cost should be 200 ultimate. Vampirism stage 4 gives 21% reduction of that cost, templar passive "Restoring spirit" reduces it by another 4% and Former emperor passive "Authority" - by another 5%. So total cost reduction should be 30% or 60 ultimate points (30% of 200 = 60). My bat swarm costs 193. What am i doing wrong?