User blog comment:Khnx/League of Math Ep.2 - All about Hentai (Penetration Charts)/@comment-6000413-20140904093238

In practice you are not saying: penetration is good. You are just comparing flat with scaling. And saying that having both instead of full flat is better after the enemy has more than 80 armor/MR.

Ok, it's better damage-wise, but have you taken into consideration cost-efficiency, too?

A real test of the MR/penetration efficiency would be to have a 3D gaph with on one of the axis the base-damage to scaling ratio for a single spell. And everything re-weighted for cost-efficiency. But I understand that's really tough work... I always planned to do that, but never found the time and will.