Would you mind casting an eye over this and check my understanding is correct?
This question refers to an NPC I'm modelling from AD&D Pegasus magazine #8. It's a 5th level Thri Kreen fighter and its base attack bonus is +7 it has +5 from its fighter levels and +2 from its hit dice. It has the Multiweapon Fighting feat. It has an 18 strength (+4). Therefore its total attack modifier is +11
Multiweapon Fighting penalties for fighting with multiple weapons are reduced by 2 with the primary hand and reduced by 6 with off hands. Normally a creature without this feat takes a -6 penalty on attacks made with its primary hand and a -10 penalty on attacks made with its off hands. It has one primary hand and all the others are off hands.
And the multi-attack feat.
Multi-attack the creature’s secondary attacks with natural weapons take only a -2 penalty. Without this feat the creature’s secondary attacks with natural weapons take a -5 penalty.
It's using a Gythka and a longsword (actually rather than a long sword it's a chain blade from Bastion Press' Torn Asunder 3rd party rule system, but for simplicity of this question let's assume it's a longsword)
The Gythka is being used as a double weapon:
Gythka: This two-handed exotic melee weapon is a polearm with a blade at each end. You can fi ght with it as if fighting with two weapons, but if you do, you incur all the normal attack penalties associated with fighting with two weapons, just as if you were using a one-handed weapon and a light weapon. A thri-kreen can wield two gythkas at once as double weapons due to its four arms, but takes penalties as if its off-hand weapon were a one-handed weapon, not a light weapon.
Therefore full attack bonuses would look like this:
+7 / +7 gythka, +7 longsword and two secondary with natural weapons +9 claw and +9 bite.
-4 penalty is imposed upon the manufactured weapons because although the thri kreen is using a double weapon (normally treated as a one handed and a light weapon therefore imposing a -2 penalty on manufactured weapon attacks with multi weapon fighting feat) he is also using a longsword which is a one handed weapon and instead a -4 penalty is imposed on ALL manufactured weapon attacks. The claw and the bite have a -2 penalty instead of -5 due to the Multi-attack feat.
Is my understanding of the total attack bonus with the respective weapons correct?
Also because it's part of the same question in the Expanded Psionics handbook on page 15 gives an example of a thri kreen fighting with 3 shortswords and seems to be implying the thri-kreen can only take a bite OR a claw as a secondary attack. I believe this is incorrect.
Natural Attacks: Thri-kreen can attack with four claws and a bite. The claws deal 1d4 points of damage, and the bite is a secondary attack that also deals 1d4 points of damage. A thri-kreen can attack with a weapon (or multiple weapons) at its normal attack bonus, and make either a bite or claw attack as a secondary attack. For example, a thri-kreen ranger with the Multiweapon Fighting feat who is armed with three short swords could attack with all three swords at a –2 penalty (the normal penalty for fighting with multiple weapons while using light weapons in its off hands) and also make a bite attack at a –5 penalty.
Because, however this is not the case when we consult the entry for thri-kreen on page 213 of the same book.
Full Attack: 4 claws +3 melee (1d4+1) and bite –2 melee (1d4 plus poison); or longspear +3 melee (1d8+1/×3) and 2 claws –2 melee (1d4) and bite –2 melee (1d4 plus poison); or javelin +4 ranged (1d6+1)
Wherein it takes a primary attack with the longspear, 2 claw attacks AND a bite attack.