Better Critical perk reads:
“When you inflict one or more points of damage to an enemy, you may spend 1 Luck Point to automatically inflict a critical hit, causing an injury.”
Does this mean that the damage required for a critical is given also when the Luck is spent? So if you hit for 1 damage and spend your point of luck does it raise the damage required for a critical to 5 (or 7 in certain cases) or does this perk simply give the critical “injury” and not extra damage?