The HR10 will work exactly the same way it does now when you put it in your bedroom-it will just output 480i if you set the output to do that. You will have to maintain DVR service on that unit and keep it active, however, or it will stop tuning locals if you leave it connected when D* removes the card and unit number. And, even if you disconnect before D* deactivates it, you will not get programming info on it.
So, provided that the card stays active, you are good to go. Don't forget to change your settings if you make any changes to the number of satellite lines you hook up.
The good thing is that you will still get programming on HD only channels with separate programming like UHD and Discovery HD, but it will output in 480 in a sort of squished mode, probably.