Something I've found about "watch now" verses downloading the movie.
On one, the watch now was 720p, while the same movie was 1080i downloaded.
As many times as I try, I never find a show downloading any slower than ~ 7Mb/s.
Recently I did have some problems downloading and along the way was able to check the different resolutions mentioned above.
The problems for watching now and downloading at very slow rates, all turned out to be on my end and with the connection to my router.
"I almost wish" I could find that there was a problem on the DirecTV side, but I just haven't seen it in maybe the past 5 years or so.