If you are thinking about Sub-Sharing here is what Dish network is saying.
I have more than 4 TV's The real question is, "How many TV's does your family use at the same time on an average day or night?" The answer to that is generally the number of TV's that will fit your household the best. You can have up to 6 receivers on a DISH Network account, but you will have to purchase any receivers over the four that are available with the Digital Home Plan. Additional receivers can be purchased from DISH Network at the time of installation for only $99/each. Additional charges may apply for any necessary materials or equipment.