Ive been playing this game since Oct.04 and I can't beleive the the number of bugs/problems that relate to NPC'S. And other odds and in's. The game i'm in now doesn"t know chainmail is AC5. You can buy it but it doesn"t up the AC from Scalemail. Everthing Otis of Nulb sells is wrong. NPC spellcasters don"t get their spell. It's just one thing after another that doesn't work.. Fix most of these problems and get the game to run correctly. All the patches and fixes in world aren't much help if they don't make the game run right. The one thing I would like to see is NPC'S can drop any item in their inventory. Burne and Fruella have all the money and jewerly and my fighters need platemail. The game is so bugged and unbalanced that even with all the mods out there,(I have most of them), the game still isn't close to right. I will admit it is frustrating and challenging but for all the wrong reasons.
If you could describe your problems in more detail, we might be able to fix them. I looked up all the chainmail armors in protos.tab, and they all seem to have AC 5. Where did you get the chainmail in question? And what do you mean when you say everything Otis sells is wrong? By the way, if you install Livonya's mod, you should be able to tell NPCs (at least some of them) to sell their stuff.
NPCbugs? I'm playing CG alignment and I have Atari2, Co8fanfix, and Temple.dll. The players came with Scalemail, AC4. I bought chainmail from brother Smyth but it did not increase the AC of the player. I looted Lareths lieutenant and he had Splintmail which it said is AC6 but when a player put it on their AC didn't change? None of the armour that Otis sells gives the AC bonus they should. I'm probably missing something. If a player has scalemail Ac4 AC19, if they put on chainmail shouldn't they go to AC20? It seems like the looted armour, like from the clerics of the fire and water temples don't give the right AC bonus, either. Do I have a major misunderstanding here?
Ac Are you considering the dexterity AC bonuses? Each type of armor has a limit on the dexterity AC bonus a character can have while wearing it. For example suppose you have a character with dexterity 18. Wearing normal clothes the character would have an AC of 14. Wearing a chain shirt (AC +4, max dex bonus +4) would give AC of 18. Wearing scale mail (AC +4, MDB +3) would give AC 17, as would chain mail (AC +5, MDB +2). Wearing splint mail (AC +6, MDB +0) would reduce the AC to 16. Also keep in mind that if your character is encumbered the max dexterity bonus will be capped at +3 for medium and +1 for heavy encumberence. Of course if a characters dexterity is 10 then they would just want to wear the armor with the best AC bonus they can find (splint would be better than chain which would be better than scale). Hope that helps!
You'll also want to consider the character's movement rate in the armor. If you've got a +3 or +4 from dex, then chain shirt is great because the armor class will be just as good (except when flat-footed) and you'll be able to move 10' further. Dwarves, though, have only a 20' move anyway and aren't slowed by armor, so they should just take things like full plate (mostly to avoid getting caught flat-footed). In essence, when your dex is high, look for the total worth of the armor (armor plus max dex), and try to get the lightest one possible with the same total. In some cases going lighter to save movement is worth a point of AC or two, and some classes have to keep to lighter armors to retain their abilities (e.g. rangers, barbarians, monks).