MLB EI is for out of market games, Sports Pack are for regional games, ESPN for the national coverage and if its not there and its on your locals you have to watch them there.
Thats the order the blackout goes in, just reversed... Local, National, Regional channel (RSN), MLB-EI.
You can't get a yankee game off the NY RSN (YES) because they only have the rights to show the game in their region for example. Same goes for their HD simulcast.
And then sometimes a local/national channel will have the rights to multiple games and you will be unable to watch any of them on RSN or MLB-EI (only the one they decide to broadcase on the local/national channel) because D* has been instructed to black them out in your area, and you then miss it completely.
MLB Blackouts suck, looking forward to football season where everything is much simpler.