This may be old hat to some, but it appears that overlapping armor types cause increase in damage from an attacker.
Here is a log from whacking the dummy wearing a shield (armor type A_SHIELD) and bracers (armor type A_CUSTOM with restrictions on "right arm" and "left arm"). When worn separately no problem. When worn together I get this:
Dummy says in English, "I receive damage from fighter. Damage type is BLADE,
raw damage is 204, body part(s) affected: right hand."
Dummy says in English, "Actual damage done: 197."
Dummy says in English, "Protection due to armor: 7."
Fighter pricks Dummy lightly in the right hand with his sharp sword.
A_SHIELD protects hands. Bracers do not.
And in the same round of fighting:
Dummy says in English, "I receive damage from fighter. Damage type is BLADE,
raw damage is 160, body part(s) affected: left arm."
Dummy says in English, "Actual damage done: 305."
Dummy says in English, "Protection due to armor: -145."
Fighter pricks Dummy just barely in the left arm with his sharp sword.
A_SHIELD protects arms as well as A_CUSTOM with "arms" restrictions.
Interestingly, "torso" protection is negated.
Any ideas?
Lash