Default [Q] Assist bluetooth stack

Anyone know if it's possible to change the bluetooth stack Assist uses? Apparently, before 4.4, it would announce text messages and caller id over the "phone audio" stack, but now only uses the "media" stack. I didn't use assist before 4.4, so I'm going on hearsay for that part. However, I can verify that with bluetooth not connected, assist plays over the phone speaker. With bluetooth connected, and using any radio input other than bluetooth audio, nothing happens. On bluetooth audio, it announces the caller id and the text messages. Only option i see is to disable "media audio" in the bluetooth options, and just have it play over the phone. Someone has got to be able to hack the apk to redirect the audio to "phone" instead of media though. If it's any assistance, from what I've read, the navigation has done the same thing.