That number was from the Shroud build, so 2d8, not 1d6. That's an extra 5.5, plus crits.
Though I was also just estimating based on the graph, not checking the exact values. For more exact values, I get 64.325 DPR at level 12 (assurance of 20 Cha) with PAM/glaive, compared to 52.625 with...