Looking the same part of code on L2JFrozen, I changed to this:
if (_skill.isMagic() && (caster.isChargedShot(ShotType.SPIRITSHOTS) || caster.isChargedShot(ShotType.BLESSED_SPIRITSHOTS)))
{
_hitTime *= 0.70;
_cancelTime *= 0.70;
_coolTime *= 0.70;
}
I think what you want to change is the coolTime (casting time). But for the effect to appear and following the logic of Frozen, it is necessary to adjust the _hitTime as well. And since you are reducing the skill's cast time, this will automatically interfere with the time the player has to cancel a skill.