Stat Block Guisarme Damage

[chopswil]

From GMF, p. 266 "Slaver". I can't make to math add up for guisarme damage,mwk guisarme +9 (2d4+3/×3).

(Two-Handed weapon StrBonus * 1.5)(3 * 1.5) = 4.5, round down to 4, +2 (Weapon Focus) = 6
SB says 3.
Where is the error in my math?

Slaver CR 3
XP 800
Human fighter 2/ranger 2
NE Medium humanoid
Init +2; Senses Perception +8
Defense
AC 15, touch 12, flat-footed 13 (+3 armor, +2 Dex)
hp 30 (4d10+8)
Fort +8, Ref +5, Will +1; +1 vs. fear
Defensive Abilities bravery +1
Offense
Speed 30 ft.
Melee mwk guisarme +9 (2d4+3/×3) or
mwk sap +8 (1d6+3 nonlethal) or
spiked gauntlet +7 (1d4+3)
Ranged bolas +7 (1d4+3)
Space 5 ft.; Reach 5 ft. (10 ft. with guisarme)
Special Attacks favored enemy (humans +2)
Statistics
Str 17, Dex 14, Con 14, Int 10, Wis 12, Cha 8
Base Atk +4; CMB +7; CMD 19
Feats Combat Reflexes, Exotic Weapon Proficiency
(bolas), Precise Shot, Step Up, Weapon Focus (bolas),
Weapon Focus (guisarme)
Skills Climb +12, Handle Animal +3, Knowledge
(geography) +4, Perception +8, Ride +7, Stealth +9,
Survival +8 (+9 to follow tracks), Swim +8
Languages Common
SQ track +1, wild empathy +1
Combat Gear feather token (whip), tanglefoot
bags (2); Other Gear masterwork studded leather,
bolas (3), masterwork guisarme, masterwork sap,
spiked gauntlet, climber's kit, drow poison (2
doses), manacles

[Rathendar]

Technically weapon focus only adds to hit, weapon specialization adds the 2 damage.

[Thazar]

There is nothing listed in that stat block that would add to damage other then STR. So all weapons would be weapon damage +3 for one handed. In an off hand it would be +1 damage and two handed would be +4 damage. The +3 is an error and it should be +4.

[chopswil]

thanks for your help