The percentage on the right side of each Sonar VAD (click here to find out what a VAD means) controls how much of the audio is assigned to each VAD.
For example, if you're playing a loud game, you can set it to 100% and tweak the volume with your headset's audio wheel. On the other hand, if you set the audio to 50% and keep your headset volume maxed out, the game’s VAD will only output half of the sound.
Hope this clears up some confusion!
GLHF!