I set the ROKU to DD+,DTS on everything. Went to NETFLIX, the audio was already set to English Original 5.1. Tried playback. No audio anywhere. Changed Netflix to English Original. Got audio in stereo to TV and AVR.
Went to the ROKU Channel and clicked on the Movie Paddington, got audio in TV and Dolby 5.1 on AVR. Went to other channels within ROKU and just got Stereo. Went to other streaming channels, like Showtime, clicked on several movies, just got stereo.
Sounds to me like the ROKU is working with the DD+, DTS settings. It is just finding the streaming information that contains DD audio. As far as Netflix goes, it is a 30 day FREE trial and the wife wants to unsubscribe from it when the trial is over, so the audio issue with it is a moot point..