Something's very wrong here... I made a two-fisted fighter, my very first one. She's a half-elf Fighter with a 16 STR, and at 1st level I gave her Two-WEapon Fighting and Two-Weapon Defense. I equipped her with a longsword and a short sword, and let 'er rip. Unfortunately, her numbers are off. According to the rules, she's only supposed to take a -2 penalty to her attack rolls with each weapon, since the off-hand weapon is light/small (I tried using a dagger too, instead of a short sword, with no changes). At 3rd level, I noticed her numbers seemed to be off. Now, according to my math, with her 16 STR (+3), her Fighter3 BAB (+3), and her 2-weapon penalty (-2), she should have a +4 attack bonus with the longsword, +2 with the short sword... the game is off by 2, leaving me with a +2/+0. When I give her the +1 Radiant Longsword from Melany's dowry, it changes to +3/+0. Is this a common error, or is this some glitch that's unique to my game? Anyone have any explanation or, better yet, solution for this?
Please post the breakdown of the attack bonus so that we can identify the problem more easily. Clicking on the relevant score from your inventory menu will reveal this. Perhaps you have Power Attack or Combat Expertise turned on. Or you may be Fighting Defensively. Also state which official patch version you are using and whether you have installed any mods.