How to calculate Potency?

Hey everyone, just one more question about this great game for now;

I am wondering how to calculate Potency, as I plan on how to build out characters like Victor. I dont see it mentioned anywhere, in game dialogue or in FAQs and other forums...

Is Potency always a percentage of the stat that the skill is affected by? IE;

Victor's "Shielding Mazurka" skill reads: "Grants HP absorb shield. Absorbs damage with a potency of 0.2 for 2 turn(s) (all)."

• Is that a flat 0.2?
• Is that a typo (should it be 0.2%)?
• Is it 0.2 of current HP levels, or 0.2 of the MND stat?

Also, see Victor's "Healing Hymn" skill which reads: "Grants HP regen with a potency of 0.2% for 2 turn(s) (all)."

• Now we see a % appear, which is why I question the 0.2 potency calculation in Shielding Mazurka... Surely, it should read "a potency of 0.2%" in Shielding Mazurka's description, right?
• As these are both healing abilities, it must be 0.2% of Victor's MND stat, right?

EDIT: Spelling.