Would like confirmation on each stack of Greased Lightning

[Mengh]

May be a bit of a noob question, but is it correct to assume that, judging from the description of GL, that each stack provides 10% more damage (along with faster recast times of course)? So 2 stacks would give 20%, 3 gives 30%, 4 40%? Been bugging me for a bit since some buffs for other jobs seem to be pretty lackluster or negligible from my understanding.

[Powercow]

Yes, it's 10/20/30/40% damage. Also don't forget that Greased Lightning's speed bonus (5/10/15/20%) isn't just to weaponskill recast, but also autoattack speed.

The reason monks have this bonus is because their weaponskill potencies are preeeeeetty crap compared to most jobs, so they need these big multipliers to make the job worthwhile.

And no damage buff from any job is negligible. Jinpu is only 13% compared to the 40% from Greased Lightning, but no samurai in their right mind would ever say "nah 13% damage aint my style."