You have a timing problem between when you ask for data and when it is ready to use.
I couldn't find an event that worked to tell you when the mount information has been cached so I bodged something up (not really tested so...)
I also moved the update code into a function to be used OnShow so it gets update each time the Config. frame is displayed.
MCL.zip
I hope it gets you closer.
Edit: I didn't check on things like frame creation so you might be getting new icon frames created on top of older ones each OnSHow and stuff like that.