val 1 is a base, 0.8 means -20% and no, it's supposed to be decrease, since it decrease vulnerability to debuff aka "anti debuff".
Do not busy, c/p of skill xml.
Oh crap. Just when I though you found a peace in your heart, I noticed your reply. There is no hope for you, you seem still butthurted and you can't understand that the problem is in you. Denial is in vogue, looks like.
Dunno how you made it, but well. If you are sure you used coords to make it like "inside a box", then change minZ and maxZ. Most likely that's your problem.