This should work right

With the app i should be able to plug in the cable to my car stereo and start pandora and then connect my bluetooth headset and still listen to pandora from the stereo and then take a call via the bluetooth, right?

Here is what happened.
I plugged the phone into the stereo, started pandora sound comes through my phone. i have to go in and select wired headphones. so then music is play out of the stereo. then i get a call press the button on the headset and the call answers but i can't hear anything in the bluetooth and nothing out of the stereo. To get the call on the bluetooth i had to unplug the cable to the stereo.

I have a Samsung Galaxy S4 on verizon.

You shouldn't have to set "Phone call audio" to "Wired headphones", if the phone can detect headphones being plugged in correctly.  The "Wired Headset behavior" / "Wired headset detection" setting should be ON for that.

To listen to music over AUX and receive phone calls on Bluetooth:
https://soundabout.forumotion.com/t23-media-audio-to-35mm-cable-while-using-bluetooth-for-phone-calls#23

I will check that out and see. Is that part of the pro version? I just realized i haven't gotten the pro version yet

The default should still work without Pro.

Ok i cleared the app data. played pandora via bluetooth plugged in headphones and it switched did that several times. then while listening to music via headphones i placed a call. for a second or two in went back and forth between the phone speaker and the bluetooth before staying with the bluetooth. I ended my call and the music started playing from the phone not the headphones. If i pull the headphones it goes back to the bluetooth. I then reconnected the headphones and it started playing from the phone not the headphones.

I hope that makes sense.

I wanted to add details to try and help work this out. The bluetooth set i use is the LG HBS730 http://www.lg.com/us/cell-phone-accessories/lg-HBS730/technical-specifications

I don't know if the type of set i was using would make a difference.

Thanks!

I did some work on that recently.

Can you try the latest Beta version and let me know if it resolves your issue?
https://soundabout.forumotion.com/f8-download-beta-versions

Ok here is what i have.

I have tried it 3 times in various situations.
I have no call audio on the bluetooth. i have phone audio like games will play sound but when i make a call it it dead silence on both ends. i hear nothing. no ringing, the only way i know its connected is the screen. i then disconnected and called the same person back without bluetooth and the call was fine. very puzzling!

I sent you an email.