I've been unable to confirm whether or not certain threat items stack.

I'm aware that 10%/15%/20% all stack with each other. (For example, Dragontouched armor with all 3 = 45%)

I'm also aware that it stacks with the Various Defender stances, and Paladin's Divine Righteousness.

However, do set bonuses stack with dragontouched?

Does the 15% from Tower of Despair Item set stack with dragontouched 15%?

Does the 20% from Levik's stack with dragontouched 20% (of course the 30% from Levik's III would stack with the 10 and 15 from dragontouched)