Lightning Mastery Question: How Does 30% Max Mana Increase Apply?

I have read the wiki, searched both the forum and online and I can't really find an explanation on this subject. The Lightning Master in particular I am looking at says:

Increases and reductions to Maximum Mana also apply to Shock Effect at 30% of their value.


My character has 300% total increases to maximum mana. That gives me 90% which should apply to Shock Effect. How does that 90% apply?

Say I shock a boss for 50%. Does the 90% just add to it for 140%? Or does it increase whatever shock is applied by 90% so if I land a 20% shock it would increase it 90% to 38% (with the 50% cap still in place)? Or is it something else?

"

Modifiers to shock effect, such as X% increased Effect of Shock, apply to the effect of the shock before the minimum or maximum effect is enforced. This means that increases to the effect of shock effectively reduce the amount of damage needed to apply both a minimum and a maximum shock. For example, a total of 100% increased Effect of Shock would reduce required the amount of damage dealt to apply a minimum effect shock to 0.06% of the enemy's ailment threshold, and reduce the required damage dealt for a maximum shock to 17.68%.

From the Shock wiki page.

Thanks. I read over that but I did not quite understand it at the time. It makes more sense now. Thanks.