I ended up connecting my S20 to the bike and phone in a way not described in your manual.
Your CASE 6 works just fine, however, with my Samsung Galaxy 5 phone paired to the S20, I get an oral prompt when a call arrives. I didn't want this distraction while riding so I paired it differently.
In this case, I paired the Phone to the BMW Navigator V and then linked the GPS to the S20. This way, I SEE a notification on the GPS screen when a call arrives and have time to deal with it. I still have GPS directional prompts and the audio system works fine, too. Bike is 2015 BMW R1200RT.