Case: A Warden has Resist 5 All Damage from some Warden feature/power. He also has Resist 10 Necrotic from his armor.
He is hit by 30 Necrotic damage from a single attack.
Does he take 15 damage, negating 10 Necrotic for the armor and then 5 untyped for the feature/power, or does he take 20 damage, negating only the 10 for his highest resist?
I know that different resistances to the same damage type do not stack, but do I consider 'All' a unique damage type or a general resistance?