Why shoudn't you charge different providers different prices? Does Samsung charge Wal-mart and Best Buy for 42" LCD? The answer is no. It has to be based on potential of subscribers. Yes there is the claim E* had it listed in there contract that they will not be more.
keep in mind this is classic Charlie on negotiating.
ESPN does have that right. The problem is that Dish negotiated a most favored nation clause in their contract which prevents this. But without such a contract clause limitation, ESPN would be free to charge different providers differently.
Full disclosure: I haven't read the contract or any of the documents related to the lawsuit, just basing my statement about what ESPN can and can't do based on what others have reported on here about the most favored nation status clause in the contract.