Dear Zachary:

The Heroic Act of Charity is "an act of charity by which a person offers to God, for the benefit of the souls in purgatory, all the works of satisfaction he or she will perform during life, and all the suffrage that will come to him or her after death. It is not a vow but an offering that can be revoked at will. Its heroism consists in the readiness to undergo sufferings here and in purgatory in order to relieve others of their purgatorial pains. The Church has more than once approved such a heroic act of charity." (Hardon's Catholic Dictionary) 

The Indulgences mentioned in the old Raccolta related to the Heroic Act still exists in a slightly different form that is more consistent with our current theological understandings. For example, a plenary Indulgence is granted for those who visit a Church or Oratory on All Souls Day. This replaces the old indulgence granted every Monday.

There is no need for an every Monday plenary indulgence for those in purgatory; for for a plenary indulgence from each Mass. The one plenary indulgence on All Souls day takes care of all that. A plenary indulgence is plenary (complete). It does not need to be repeated for those in purgatory since they do not continue to sin. Thus, the one plenary indulgence on All Souls day is more appropriate as that is the Day set aside for them and more consistent with the theological understanding of purgatory and indulgences. As for the time, there is no time in the spiritual world, which includes purgatory. Thus, receiving the indulgence today, or next year on November 2nd make no difference.

We also receive numerous partial indulgences each time we attend Mass, and in some cases a plenary indulgence. All these indulgences gained by those who have made a heroic act are applied to the souls in purgatory.

The revisions of the list of Indulgences made by Pope Paul VI was motivated by focusing on the most important prayers and indulgences. In his Apostolic Constitution, Pope Paul VI states, "It has also been considered fitting to reduce appropriately the number of plenary indulgences in order that the faithful may hold them in greater esteem and may in fact acquire them with the proper dispositions. For indeed the greater the proliferation (of indulgences) the less is the attention given them; what is offered in abundance is not greatly appreciated. Besides, many of the faithful need considerable time to prepare themselves properly for acquisition of a plenary indulgence."

You can make a Heroic Act at any time you wish if God is calling you to do that. Yes, it is revocable at any time, but as long as it applies, all satisfactions gained by you, all indulgences, partial or plenary, received by you, will be applied to the souls in purgatory.

We should focus on "score-keeping" but on the love of the brethren knowing that any and all satisfactions and indulgences that we may attain will go in love to our brethren in purgatory.

God Bless,
Bro. Ignatius Mary