Your chance to hit with ranged weapons is determined by perception and not by dexterity.
Then explain why my mage with a low perception can hit better than an archer with a higher perception.
Does your mage have a bow equipped? I think, he probably has a staff as a weapon, doesn't he? Staff is an intelligence-based weapon, so the chance to hit is determined by intelligence. So, if your mage has a very high intelligence, then his chance to hit with a staff is also very high.
The chance to hit with ranged weapons (which is the same as accuracy) is determined by perception.
