I read the piercing description, and it says this:
Against an enemy of the same level, you have a __% chance to deal a critical strike with this Element, increasing your damage by __%. Attacks that do not crit deal __% additional damage.
I was kind of alarmed, because it says piercing works against an enemy of the SAME LEVEL. My level is higher than my enemies', because I spend way too much time unnecessarily training (it's safer that way). Anyways, does this mean my piercing isn't actually doing anything extra?