Weapon Skill Damage

From FFXI Wiki

Calculating Physical Weapon Skill Damage

Similar to Physical Damage, Weapon Skill damage is calculated as :

Damage = Base Damage * pDIF

In addition to Weapon Base Damage and fSTR(2) in normal physical damage calculation, Base Damage in Weapon Skill get an additional bonus from your stats, called WSC (Weapon Skill Secondary Attribute Modifier).
This new base damage value will further be adjusted by, a TP Multiplier, called fTP. This value may varies depending the amount of TP you have and Weapon Skill you perform.

WS Base Damage = ( Weapon Base Damage + (Ammo Damage) + fSTR(2) + WSC ) * fTP
WS Damage = WS Base Damage * pDIF