shaiya Assault Lapis question

whats the different bettwen assault lapis and craft lapis?

lets say im a fighter, i have a craft lv6 lapis which is + 30 str and i have a max assault lapis which is + 40 atk, so whats the different?

cause 1 str = 1.3atk, 30 str = 39 atk .

wrong section.

As far as I know, Assault just increases the damage threshold for your character. Your weapon has an attack like 100-150 and the Assault lapis will increase that allowing you to do further damage. Just like the Deceive (I believe it's called) increases the minimum damage threshold allowing your hits to be more consistent in damage. Correct?