People here focus on a word or few words, but never expound their thought process because....the devil is in the details, always. Not just the words Utility Model.
If you look closely, the Calhoun plan just used the CBO analysis to derive $50-$100b of warrant value. Which if you look at the CBO model in detail it clearly assumes full value (no writedown) for the snr pfds with residual / additional left over value of $50b-$100b. No snr pfd write down.