Thank you so much for these helpful comments. I agree any changes in the iPhone settings seem to switch it back to 360 degree mode … perhaps even opening other Apps on the phone.
I personally find that 360 directional setting feels like my head is suddenly full of cotton wool … sound feel indistinct & fuzzy😂
so I wish I could “lock” it into 70 degrees forward so it defaulted to that rather than 360.
I’m still INCREDIBLY impressed & grateful for the App … how wonderful to hear SO much better … bless this miracle of technology & the clever guys behind it all 
Jamie