Could someone (Boeroer, i'm calling to you) explain DoT mechanics in Deadfire?

In PoE 1 each damage tick was reduced by 1/4 DR. Now we have AR - how this parameter interacts with DoT? Does DoT damage have one initial check vs AR, or each tick?

 

P.S. I've tried search option but find nothing.

Edited August 25, 20187 yr by Phenomenum

I haven't tested in scenarios where AR rating changes through the fight, however most DoTs will display an "x damage per 3.0 seconds for y seconds" in the combat log on hit. If you hold shift over that it will show the AR/PEN values and if it is over/under so I am assuming it is only calculated on hit. This makes sense in that a crit provides +50% PEN, and since each tick doesn't have its own roll, that same bonus PEN must apply for the entire duration.

 

Obviously only significant for non-raw damage DoTs.