Guild Wars 2

Hey, was just wondering how does this skill work? In my tooltips looks like it does 1 stack of burning, but in reality it does no burning. Also the tooltip on this site is different http://en.gw2skills.net/editor/ .

It used to extend burning by 2 seconds when you used it on a enemy that was already burning, this was still when burning didn’t stack (it would do like 1100 burning damage on a cele build). When burning stacks were introduced (now) it still works the same way (only on already burning enemies) but it does less damage (1 stack 2 seconds = 654 on my cele build) and the tooltip was changed from “extends burning duration” to “burning (2s)” which is not true when used against non burning enemies.