Reduce Confession Stacks to Two

[kikix12]

How is 10 seconds fine? Most movement mechanics take around 10 seconds to go off so they drop off by the time the boss does his thing, Bosses have cast times and stacks only apply to targets that get hp healed while in combat, doesn't apply to full hp people.
10 is to short, 30 should be fine.

If someone is at full HP, then they don't NEED any more healing. So them not getting any heal from Plenary Indulgence is irrelevant.

If the boss hits the party with strong AoE, you will use two or more Medica to even get the party to full HP. Medica and Medica II are comparatively weak (on a single target and in instant healing, not over time) in healing potency versus Cure tree of spells, so a heavy AoE will very much require multiple AoE casts to heal. That means multiple confessions well within the 10sec range, all of which will give confession. Instead of casting that additional Medica, just cast Plenary Indulgence. You'll save time and MP both.