Board Thread:General Discussion/@comment-174.112.7.243-20130219054819/@comment-5917342-20130219060633

Test Report:

I tested two spells.

1. Invisibility: one hand cast cost 199 magicka, overcharge cast with both hands cost 557 magicka.

2. Paralyze: one hand cast cost 50 magicka, overcharge cast with both hands cost 140 magicka.

So the result is: overcharge cost 280% magicka. That's 180% extra.

(140 / 50 = 280%)

Dual casting master level spells do not need extra magicka because all master level spells require boths hand so they cannot be overcharged.