I was under the impression I could spend Elder Charms of Good Fortune on additional rolls for loot from bosses such as the Sha of Anger and Galleon - for instance, I fight them once that week, get my regular loot, my additional roll. If I fight them again, I don't get regular loot again, but I still can spend a Charm to get another additional roll.
Did this change, am I mis-remembering, or has something gone wrong?