Evolith For BLU Spells

ok I know a lot about BLU but was wondering if anyone had tested the Evolith that says "Physical Blue Magic: Atk +1-4, I'm not sure on the blue magic formulas and how it would work with those but was just wondering if anyone has tested or knows

I not completely read up on it but I think it just gives that amount to the attack portion of pdif.

Which from what I've read it takes 1 skill or 2 str to increase it with no other ways other than like this evolith.

So I guess you could count this as 1 for 1 like blu skill minus the part that can add to your base dmg