Natural Attack Questions

[Rhaddrain]

Natural Attacks:
I see these everywhere but they can be rather complex, lets say there was a Glabrezu he is a good example of a weird natural attacker.

Melee 2 pincers +20 (2d8+10/19–20), 2 claws +20 (1d6+10), bite +20 (1d8+10)

(I'm putting anything that modifies the attacks down here but here's a link incase im not looking at something important)
http://www.d20pfsrd.com/bestiary/monster-listings/outsiders/demon/glabrezu

Str 31
Base Atk +12
(I'm also pretty sure this is assuming that he's using power attack, so -4 attack +8 dam. WITHOUT power attack it would be +22)

that would mean he should have +18 to hit not 20 if im not mistaken...
Also, since these can't all be primary doesn't he have penalties to some of these attacks?

Finally, wouldn't the damage be lower? Unless these are all treated as primary... some clarification on what's primary and what's considered secondary would be helpful.

[Eltacolibre]

Actually they can all be primary, as weird as it may seem, you can have multiple primary natural attacks.

[Nefreet]

BAB of +12
Str of +10
Size penalty of -2

Power Attack is never factored into the statblock. That's up to the GM to work out (and yes, it'd be -4 to-hit).

All of these attacks are primary. Primary and Secondary rules changed from 3.5 to Pathfinder.

[Avoron]

What Nefreet said. The thing you missed was size penalties.

With power attack it would be +16 attack, +18 damage.

[Rhaddrain]

So if he did full attack it would be all of these modifiers?

[kestral287]

Yes, his full attack is all five of those attacks, all at that +20. Unless he decides to Power Attack of course, then all are at +16.