I believe the descriptions of fStaminaAttackWeaponBase and fStaminaAttackWeaponMult are materially incorrect. Testing weapons in game with weights of 5, 10, 15, 20, 25, and 30, the stamina cost was consistent with 40+(2*<weight>). Ergo, the calculation using the settings are likely:
(fStaminaAttackWeaponBase+(<weigt>*fStaminaAttackWeaponMult))*fPowerAttackStaminaPenalty
Using fStaminaAttackWeaponMult=2 and fPowerAttackStaminaPenalty=1 results in 20+(2*<weight>). Tho I'd like someone to confirm my findings before I change something willy-nilly.