Spotify "Prefer high quality stream" conf setting

I have a peculiar issue with my Raspi / Volumio setup. My issue is that hard copies of music (both mp3 and flac) sound dramatically better than Spotify. With high quality streaming I know the differences should be nearly imperceptible, so I am suspecting that the “Prefer High Quality Stream” setting isn’t actually giving me the 320kbps streams from Spotify.

However, I’m not sure how to test this theory. Changing the configuration in the UI doesn’t reflect any changes in /etc/spopd.conf. Does anyone know where this config option is actually stored? If it is supposed to be that file, what should it look like when it’s “on” and when it’s “off”?