Level 5 Shield Boomerang damage calculation

[kysp]

I think I've figured it out for the case with the + 4 Cross Shield. The formula is:

damage = [(ATK * 250%) + 5] * 160% + (shield.weight/10) + (10 * refine).

And yes, it implies that Cross Shield does 60% increase instead of the 30% in the description. That's odd.

For exemple, with 265 ATK with + 4 Cross Shield on monster Drops (0 DEF, 3 Vit): damage = (1068 + 20 + 40) - 3 = 1128 - 3 = 1125 by the formula. I tested it on poring island (on hero) and it does exactly 1125 all the times.

I compared the results given by the formula for Poporing and Poring with empirical testing (for each one), and the damage is the same!

You may wonder where did i came with the + 5 in the expression and the 60% increase. First, I suspected the % increase was wrong, so solved an equation using the real damage I was getting in the game for an unknow x being the % increase. You get a value approximately 160%. So by intuition I added 5 to the "first" damage, and redoing the calculator job, it matched perfectly.

I think the + 5 is from the +4 refine, so if you have + 5 refine, use + 6, etc.

I don't have another Cross Shield with different refine to test. So please, someone test it!