It would be simple minded to think Dish has not done their own math on the business side of this equation.
You'd think so, wouldn't you? But the reality is that many, many business decisions are not made based on the math, and are instead made based on emotions and egos of the people in power (people are people, after all...) I've seen it a million times. Maybe I just worked for dysfunctional companies, but people at the top will easily reject the fact-based, mathematical argument if their gut wants them to go a different way. I've seen entire businesses started up or ejected, despite the math being against them. And in this case, this dispute has all the markings of a battle of egos between the two Charlies involved.
(As a side note, if JP Morgan Chase had followed the math, they probably wouldn't have accidentally lost $3B this quarter. Whoops...)