Because you also have 30% cost reduction (LA, class/racial passives, seducer set).
% cost reduction is applied after flat cost reduction.
Opinions are like buttholes : Everybody has one, and they usually stink.
3 things to reduce stamina/magicka imbalance :
- Use magicka to block abilities costing magicka, instead of stamina.
- Add % damage reduction to heavy armor.
- Add block penetration to 2H.