I have noticed that PLD spell, Spirits Within does different amount of damage depending on when it is used. I am just trying to understand why because I do not see a mechanism that enhances its damage. In all the scenarios below, I will at maximum HP.

Scenario 1: Spirits Within (with no skill beforehand) -> around 160 damage
Scenario 2: Fast Blade -> Spirits Within (spamming it; before the animation of fast blade fully ends) -> around 175 damage
Scenario 3: Fast Blade -> Savage Blade -> Spirits Within (Again, before the animation of Savage Blade fully ends) -> around 190 damage
Scenario 4: Fast Blade -> Savage Blade -> Rage of Halone -> Spirits Within (Again, before the animation of Rage of Halone fully ends) -> Around 210 damage

From what I see, the basic Halone combo do not have any damage enhancement aspect. However, using Spirits Within immediately after a Halone combo does the most damage for that spell. Anyone know the reason of this?