It is well known that for Paladins and Rangers the caster level does not equal the character level. However, the BG2 manual states that their caster level starts with a value of 1 at character level 8 (for Rangers) and 9 (for Paladins) and continues to rise by one point per character level from that point onward. That part appears to be true. However, the manual also states that the caster level caps at a value of 9 and never rises above that. According to my testing, this part isn't true and the caster level for Paladins and Rangers keeps improving even further. In fact, I believe that their caster levels are actually calculated like this:Ranger
Caster Level = (Ranger level - 7)Paladin
Caster Level = (Paladin level - 8)
A few simple tests can easily prove this. For example, a level 23 Paladin is be able to summon a Skeleton Warrior by casting Animate Dead while a level 27 Ranger gets 25% Magic Damage Resistance by casting Spirit Armor.