I assume you compare the dice roll against the Impact Icon on the attacker card, right?You compare the dice roll to the Impact Value of the weapon that fires.
If the defender has a "hit the dirt" token on a card, smoke grenade token on a card or smoke screen tokens on the board you add those modifiers to the Impact Icon on the attacker card before rolling the die, right.Yes
Terrain Modifiers. The numbers shown on the Impact Icon are added to the impact icon of the attacker card, right? Yes
You add (malus) or subtract (bonus) the modifiers :
Bonuses for Impact Value = -x/-y
Malus for Impact Value = +x/+y