HC:
From the Baltimore Catechism the nuns used with me:
"439. How does the Church by means of indulgences remit the temporal punishment due to sin?
The Church by means of indulgences remits the temporal punishment due to sin by applying to us from her spiritual treasury part of the infinite satisfaction of Jesus Christ and of the superabundant satisfaction of the Blessed Virgin Mary and of the saints.
For there is one God, and one Mediator between God and men, himself man, Christ Jesus, who gave himself a ransom for all, bearing witness in his own time. (I Timothy 2:5-6)
440. What is the superabundant satisfaction of the Blessed Virgin Mary and of the saints?
The superabundant satisfaction of the Blessed Virgin Mary and of the saints is that which they gained during their lifetime but did not need, and which the Church applies to their fellow members of the communion of saints. "
I was 10 when VII closed (1965) so you're probably older than I since we had electric lights then :)
The Irish Ursuline nuns taught nothing like Mary being the only way to Jesus back then either. I got caught in the beginning of the VII implementation in 8th grade though. The poor nuns having to change to those short habits and their beautiful crucifixes changed to small crosses and guitar masses etc.
High School was with Josephites and I don't have such good memories of them I'm sorry to say