Just a theory, but the most likely explanation for the mistaken 15 hit enrage is either A. Not a full swing on one of the hits. Or 2. Swordbearer is mid-swing so doesn't notice the enrage from the 14th hit as he swings again almost immediately. I'm finding the link for another damage table on Crota which is much more readable then the one above. It shows the damage at 14 slams and Crota's life at that point in numbers, and the % of life he needs to be at to queue the enrage. Will post it shortly.