Individual Track Volume

Unless the output amplifier is “saturated” at 120, then anything above that is going to have a lower signal-to-noise ratio.

By turning up individual track volumes you increase the voltage of the input signal to the op-amp. When you turn up the master output you are increasing the current to the op-amp. Input voltage and the supplied current are two different phenomena and will behave differently.

It is often best not to have either turned all the way up.

Edit: 120 is an arbitrary value. I don’t know where that saturation knee is, but Elektron is pretty good about tuning their circuits, so I do imagine you can increase the gain quite a bit without distortion.