So I have been chewing through forums about this and from what I understand is this. With all the additional feats that follow both feats. A person with TWF ITWF GTWF will have their normal attacks plus any penalties that apply would allow at 20th level (4 main hands and 3 off hands). Then with MWF for those of 3 arms get at the same level and same class only 6 attacks (4 main and 2 off hands). Now with a 4 arms races with the same setup this gives them (4 main and 3 off hands). MWF only has one feat which lower the penalties for off hands and since there is no further feats under this feat there is no additional off hand attacks in later swings. So correct me if I am wrong the difference between the two feats choices is one does three off hand over three attacks out of four and the other gets three off hands with the first (based on a 4 armed race).
I don't fully understand your last sentence, but I think you have it, up to the points that (a) there's a lot more difference before level 16 and (b) the total penalties differ such that MWF still has an advantage.
Yes.
The benefit between MWF and TWF is that A. It's less feats. B. It's just Off-Hand Penalties (-2), and C. the damage output would be the same in the later levels, though MWF would win out because each weapon only suffers -2 to-hit, whereas TWF has to deal with iterative penalties on top of it for their off-hand weapons.
The downside to MWF is that you have to invest your WBL into your other weapons equally. Getting 4 +10 Weapons costs 800,000 gold, which is about 95% of your WBL by 20th, whereas TWF only requires about 50% WBl investment. There's also the factor that there's really only one PC-playable race (Kasatha) that can actually pull MWF off, leaving MWF to be primarily a GM-specific option.
