Decided to move this from the Lexington thread...
The $10 MiLB.TV subscription add noted in the LEX thread is only for
new MLB.TV subscribers. If you are an existing MLB.TV customer, you can call MLB.TV Customer Service at 1.866.800.1275 (then '3', then '2'), they can give existing customers the $10 deal, but it requires them to cancel your existing MLB.TV subscription and then re-enroll you, adding the $10 MiLB.TV subscription at this time. Pain in the ass (as I had to take care of office crap before I was finished with the transaction...).
Anyway... if interested here is the MLB.TV support forum thread related to this issue:
LINK