Target has a spell resistance of X. The moderation team and community utilizing reddiquette work together to create a respectful community where opinions about the game can be discussed. Spell penetration reduces the target's resistance to your spells; it is a different mechanic from spell hit rating. Is more spell damage preferable to spell penetration for PVE play? Aside from that, he's right, Penetration and Resistance are a completely different step from Saves and there is no stacking involved with Spell Penetration and Spell Focus. The only area where his explanation is wrong is in HOW Spell Penetration is actually punched through.