Last week had xfinity installed, triple play 125 channels. On my 2nd Samsung TV(2016) I bought a Roku streaming stick. When I go to Home, then Xfinity Beta , and hit Live I only see channels starting at 1300 thru like 3800+. I am disappointed that I don't see my local channels and thinking about returning my Roku and getting the Xfinity box for $5. a month.
You should see the same channels on the app as you do on your X1 box. Xfinity does map another instance above channel 1000. You can set 'favorites' using the X1 box or the web streaming site to make it easier to select the channels you use with the roku remote with no number buttons.