Do I understand manyshot correctly? (3.5)

[holywhippet]

Do I understand how this feat works correctly? You use up your standard action to fire extra arrows. At first it's two arrows total, then 3 at BAB 11 and 4 at BAB 16.

But you get a -4 penalty on your first two arrows to start with and when you fire more than two arrows, each of them takes another -2 penalty cumulatively.

So at BAB 16 your arrows would have attack bonuses of +12/+12/+10/+8? But your regular bonuses at BAB 16 are +16/+11/+6/+1 at BAB so you get a penalty of 4 on the first arrow, a bonus of 1, 4 and 7 on the last 3?

On the other hand at BAB 6 your bonuses are normally +6/+1 but with manyshot that turns into +2/+2.

At high levels I can see it being an advantage since your third and fourth attacks will have better bonuses but for low levels it's more of hindrance.

[Seppo87]

Manyshot uses a single attack roll for all arrows.

At BaB 6 it's 2 arrows. Both use the same attack bonus, which is +2 (the result of 6 -4).

It's not +2/+2. It's just +2. You only get to roll once. Either both arrows hit, or both miss.

Then at LV11 you can fire 2 arrows at +7 or three at +5

At LV 16 you can fire 2 arrows at +12, three at +10, or 4 at +8

No matter how many arrows you choose to fire, it's always a standard action and all arrows use the same attack roll.

Is it advantageous? Depends on your build.
There are fine examples of Manyshot abuse, especially if you can get many standard actions per turn and stack up a lot of flat bonuses on damage, i.e. factotum

[Crake]

it works really well with bardic music and ranger favoured enemies to stack up some pretty huge damage bonuses. Also, if you later down the track get greater manyshot (in the XPH, though not a psionic feat at all, just a wierd place to put it), you can also get critical/precision damage on every arrow fired, though i believe with that each attack roll is rolled separately.

[Seppo87]

Greater Manyshot is imho worse in some cases, i.e. if you want to use True Strike or Factotum's cunning insight to add a bonus on your next attack roll you'd rather have that bonus applied to all arrows.