Return of Reckoning

I've been trying to figure out how crits work in combination with AoE and DoT effects but haven't been able to find any source on this.

Mainly:
* With DoT (or HoT for that matter) - is crit chance calculated for each tick or once for the whole duration?
* With AoE - is crit chance calculated as a whole or per target individually? In case of the former, how does this combine with individual crit resistances?

Can't answer it completely, only afaik.

If I throw a Dot AoE Grenade each one hit by it gets his Crit individually.

Meaning target 1 and 2 get a normal tic.
Target 3 gets a Crit.

Next tic one or more different ones are getting their Crit.

Afaik every hit gets his own crit calculation, depending on the targets chance to get critted and your own crit chance. No matter if dot, aoe or whatever.