Lothair's passive skill

[trail patrol]

Server S2 -52 user ID Pnzed, Considering the passive description each stack of toxin should do the 40% of the hero ATK (given that the dummys HP is high enough to cap the limit), by looking at the video the dmg done by the passive is 838 (for 1 stack) which is actually around 50% considering a 1691 basic Atk. Am I interpreting the skill in the correct way? If so I'm not complaining about the % cause 50 is good, but I think that the description typo should be corrected.

[onyx egret]

But you get +20% from skill level. 40% x 1.2= 48%, close enough to 50% you see.

[trail patrol]

Right but my skill is at level 1 I haven't upgraded it yet