Certain replacement values are referred to as “locked.” Locked combat values ignore all other replacement values and modifiers. Whenever a combat value is calculated and a locked replacement value is applied to it, the locked replacement value is the only replacement or modifier that can affect that combat value, and if a specific number is locked, that number is the only possible result of the calculation. Unless otherwise specified, locked values last until the end of the attack that caused the locked value. If there was no attack in the action that resulted in the locked value, then the locked value lasts until the action resolves unless specified otherwise.
•The current rule of the land is "Replace then Modify". Under the old PAC wording , if you were to modify Wolverine's damage by +2, then use Blades / Claws / Fangs, the result would be (A) Roll for damage and replace the combat value with the result, then (B) apply the +2 modification. See the problem? If you roll a  with B/C/F, you could end up dealing  damage! The new wording of the PAC prevents this, because your B/C/F damage roll is now "Locked". Since it's "locked", the +2 modifier fizzles and is never applied.