Disclaimer: Funny mix of ranting and genuine questions ahead. Even I cannot clearly tell which parts are ranting and which genuine questions.
As I was reviewing the armour sets I have collected troughout the game, trying to decide which ones to keep and which ones to sell, I became so confused with all the numbers and modifiers. I know the basic idea: The lower the AC, the harder you are to hit. However, the specific details are so confusing.
I attach a saved game that contains several confusing details:
My bard (charname) isn't wearing anything that improves his AC. Still, he has a -2 modifier to his AC vs. missiles. Where does this come from?
Minsc is wearing:
A red dragon scale: AC -1, -4 vs. slashing, -2 vs. piercing and missile. The Destroyer of the hills: AC +4 vs. crushing attacks. As a result, his AC is -3. However, he has modifiers for all four types of damage: crushing, slashing, piercing and missile. So what does the -3 mean? Vs. what does he have AC -3?
Keldorn is wearing the Firecam Armour, AC 0, and nothing else that affects his AC. However, he has bonuses to his AC vs. slashing, piercing and missile. Where do these come from?
Apart from that, the descriptions of the items seem wrong. The descriptions of shields, for instance, say their ability (weird that a shield has an ability, but that's a different story) is AC +1, when it really is AC -1.
Finally, what does the word "modifier" exactly mean? The Destroyer of the hills modifies the AC vs. crushing. The Ring of the princes modifies the AC in general. Why is only the former listed under modifiers?