Overflow Damage
From Legends of Cphera
Overflow Damage is the extra damage dealt in an attack caused by the attacker's attack value exceeding the defender's defense value. It applies to mêlée attacks and ranged attacks within 30 feet.
This extra damage is only calculated when the defender is denied his Agility to his AC.
By default, this damage is equal to one quarter of the difference between the attack and defense values.
Characters or other targets, such as objects, which are for any reason are immune to Critical Hits are also immune to overflow damage.
The efficiency of Overflow Damage is increased by the Precise Strike, Improved Precise Strike, and Greater Precise Strike feats.