Hi @munga - did you find a solution to this?
I would like to do the same. I am constantly changing the volume up and down in my car due to the differences in volume levels of my tracks. I have just learned how to go through the process of volume analyzing on all tracks. I now have those set and listen to my MB library using the smart gain playback setting.
I am doing two things, exporting these files to a folder to then drop into itunes to sync with my phone. I am also copying those files over to a USB memory stick to use in my car, when I want a little bit of a better audio experience. I have a Lexicon sound system in my car, so playing via the USB stick is a huge improvement over the lousy audio quality that comes out of the iphone through carplay via USB.
What I'm trying to figure out is, how can I permanently apply the volume gain changes to the files I export from MB that I load onto my iphone and USB memory stick. I just delete these files after I copy them over and I dont do it often. Is there a simple way to do this?