Can't change Handbrake audio bit rate I'm trying to compress video files using handbrake.

While I'm managing to bring the video bit rate down, the audio bit rate is always at around 380kbps, no matter what I set in the audio settings tab. See below images for details.

What am I doing wrong?
What tool do you use for showing the Audio bitrate?
Try MediaInfo to make sure that Handbrake is the problem here.
But as far as I can see, you aren't doing anything wrong (besides setting the audio bitrate this low ;) ).
The avcodec AAC encoder also has quality settings, you can try these out as well (Couldn't hear any difference for settings 3 and higher, but was able to hear some slight artifacts at 2, never tried 1).
For best compression use MKV container with opus audio and x265 video encoder.