One of the issues about Purgatory is there is no time as we know it there. The time issue deals with the temporal punishment due for sin. As any offence deserves restitution, ie you steal ten dollars from someone you have to pay it back. The old Testament requires a restitution plus an extra fine. If you don’t make restitution, and are caught, the fine is double your offense.
While we cannot pay for the offense against God, only Christs sacrifice can do that. We do make restitution to God, and show our remorse and willingness to make up for our slight against His law, as well as thank Him for our forgiveness by Christ’s atonement for us by offering Him our Penances, (an ancient way of saying repentance) Of their own they are worthless, but united to Christ and His will they are uplifted and made acceptable. “Time” in purgatory, and Indulgences are based not on what goes on in the purification to prepair our souls to see God face to face, but are based on the amount of penance or time a penance was imposed in the early Church. An example of these penances would be not eating meat for a month, or being excluded from the Mass of the Faithful and communion sometimes from the time the sin was confessed, (in the early Church usually in public) until one’s deathbed. Talk about a strict penance.