Originally Posted by js1975
to apply this concept to a sin, if I missed mass, then I would not technically need to go to confession as long as I had perfect contrition?
Missing Mass on occasion is not a mortal sin.
If one commits an actual mortal sin, one should say an act of perfect contrition, then go to Confession at one's earliest opportunity. Yes, you are still required to go to Confession. But if you are unable, you are still forgiven by the act of perfect contrition.
You cannot be certain if your act of contrition is of the perfect type, and is sincere. But if you go to confession, you are forgiven even with imperfect contrition, so there is a greater degree of certitude. Therefore, the Church prudently requires confession even after an act of perfect contrition.