One response says that the earlier power need not persist numerically; a similar instance may be created again. This is described as the renewal of similars (*tajaddud al-amthāl*).
Granting that possibility gives a sense in which capacity existed earlier, but the particular power associated with the deed may still be the instance occurring at the time of the deed. The argument shifts from persistence of one numerically identical power to successive, similar powers.
The issue is whether renewal establishes the actual effective power before the deed or only a prior capacity of a different description.