by Youfie » Sat Jan 02, 2016 4:27 am
Long story short, Blizzard / Mangos rounding sucks, we don't really know how it's done, but the Talent works, your Drain Life is just too low level yet.
I know according to basic maths you should see a little difference, like you said, but it happens to be computed differently, for some reason. When it comes to very small values & shit, the way the game rounds number is weird.
Maybe the game just calculates 1%, rounds it, and then multiplies it by the Rank of the talent (in your case 4). So 18x1% = 0,18, and since it seems the game rounds numbers by truncating them (this is what you can see elsewhere in the game at least, from what I read), it comes down to 0,18 -> 0, 0*4 = 0.
This is just a shaky theory, I have no idea if this is how it really works, but what you need to remember is that the Talent works, but for some unknown reason it doesn't apply to values of Drain Life that are too low. I don't know either if this precise behavior of the talent existed on retail, I wouldn't be surprised since the game always tended to be a bit capricious regarding rounding & shit.