You need your HAs to have a feature within them, I think it’s called FlexVolume, if you have FlexVolume in your HAs then eventally the volume will stick at the level you put it at.
If you don’t have that feature, it will revert back to what your Audi set it at when you turn HAs off. I had the myPilot and if I turned volume up with myPilot and then turn HAs off, the myPilot would be showing the wrong volume. You would actually be at your volume that the Audi set it at and th myPilot would be wrong.
if you turn the myPilot off and not your HAs then your hearing aids will still be at a higher volume but your myPilot will show it at the default volume.
EDIT- Its actually called Self Learning - Logs, learns and adapts user volume preferences. If you don’t have this, then your HAs will revert back to the default volume no matter what your myPilot says