Sorry for the delayed response.
If you set output attenuation that will be not make any difference in the LED display. They are show the value before the output attenuation.
But you can switch the uTrack24 to post fader mode (Menu/Playback/Multitrack mode options/Outputs) in this case the LED’s will show the post fader value.
With this setup you will be enable the function where the uTrack24 DB25 output levels will follow the mixer levels from uTool.