The Ranged +X should say: This creature gains + X attack dice when it makes a ranged attack. Has no effect on zone attacks. Does not grant a ranged attack if this creature does not have one. If the attack makes multiple attacks against the same or different objects, it gains this bonus only for the first attack it makes.
This is how all similar traits work, including Bloodthirsty +X, Mana Drain +X, Mana Transfer +X, Melee +X, etc.
So, for instance - with Chain Lightning, the first target would get the bonus, and subsequent targets would not.
