The Church has always used terms such as partial and plenary to describe indulgences. Time units used to be included by analogy, that is, they established an analogy between actions meant for the laity living in the world and penitential actions meant for religious monks living in community.
My objection is that the term "lessen" is applicable, even though time measure does not properly apply. If we can speak of partial indulgence, we can speak of partial suffering.