I don't have to use my iPhone as my audio source to hear the directions over the Jeep speakers; however, my 730N system recognizes the directions as a phone call, so I get the "Phone call completed" line after every direction...which is annoying as hell.
I'm usually listening to Spotify on my drives where I need directions anyway so it's been awhile since I've done this but I believe if you simply connect your phone via bluetooth and the music will play through the Jeep speakers, then switch to radio/sat/whatever, directions will still come through the Jeep speakers via your phone. I know this has worked for me before but it's been awhile since I tried it and I may have added another step that I'm not remembering. I'll test it this weekend.
My directions come through fine from my iPhone. The catch is you need to use that for your audio input. If I am streaming music off my iPhone the directions also come through the speakers. If I'm using a different audio source (SAT/AM-FM/USB) the directions just come out the iPhone speaker.
Are you saying that you can use your android for directions while using another audio source and it still interrupts the music to give audible directions?