Are the bonuses from Silent Killer cumulative?

Question

Are the two bonuses from Basic and Aced cumulative, or does the Aced level list the total bonus damage?

With both levels, will I have +30% or + 45% damage?

Answer 1

It think doesn't stack.

Silent Killer

Basic (4 pt): You deal more damage with all silencer weapons. Deal 15% more damage with silenced weapons

<p>Ace (8 pt): You deal even more damage and have a chance to pierce armor.
Deal 30% more damage with silenced weapons. 15% chance to pierce armor <strong>(does not stack. 27.75% with both skills)</strong></p>

And

c4ndlejack [guide's author] 9 Sep 2013 @ 2 h 55

(...) Silent killer adds 30% aced.

Source : http://steamcommunity.com/sharedfiles/filedetails/?id=169443444