If NBCSN Philly is included in your package and you live in the area I'm sure that will change.
Tom, just tell it to record all the shows that the guide currently shows as airing between between 7pm and 11. You'll still want to check on it of course in case the whole thing goes away when they update the guide. I assume the DVR does have a standard "add a half-hour or hour" feature for extra innings? (I don't have that on my ATT Now app, alas, but it's rare I DVR sports there since everything is separate apps anyway.)
Kind of glad I'm out of market, MLB.TV is hard to beat. Never have to DVR, can use the radio announcers, can pause live or start at any inning if I missed the start. I assume even NBCSN's app/streaming for subscribers is not as good.