Here is a little more from nwnwiki on a ranged touch attack and how it is calculated:
When you are the target of a touch attack, your AC doesn’t include any armor bonus, shield bonus, or natural armor bonus. All other modifiers, such as your size modifier, deflection bonus, Dexterity modifier, and dodge bonus (if any) apply normally (or, if flatfooted do not apply with the exception of deflection).
The attack and defensive values are calculated as such:
Attacker: 1d20 + base attack bonus + bonus stat (see above for type) + attack bonuses
Defender: 10 + Dexterity bonus + Dodge AC bonus + Deflection AC bonus+ Size modifier