You are wrong in the calculation of accrual to the convert. It stops after five years. They are capped at around $60 million more, or $216 million ($816 total). After that their upside is gone, unless they convert. What do they do then?
As to them paying dividends on the preferred, they might not, but that hardly has any big impact on the final outcome. (It's only around $9 million a year).
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