I know that fighting with two weapons or a double weapon allows you to make an extra attack per round with the off-hand weapon, but if you have more than one attack in a round with a full attack, does the penalty apply on the main hand attack for all attacks?
Say i'm level 20, with full BAB, so I have a BAB for a full attack of 20/15/10/5, assuming i'm fighting with two weapons, have TWF feat and using a light weapon, is my full attack 18/18/13/8/3 or is it 18/18/15/10/5? Or is the extra attack generated per round also generated per attack in a full attack so I would have an 18/18/13/13/8/8/3/3 for 8 attacks?
At level 20 and assuming:
the attacks are 18/13/8/3 for primary weapon and 18/13/8 for the secondary.
You basically get one 'extra' attack for each feat in the TWF chain, the most attacks you will get is 7 assuming feats and full BAB only (4+3).
You take a penalty on both attacks as per the table (depends on the types of weapons used).
@20 just using TWF, 18/13/8/3 + 18