I tried that yesterday just to be sure that it’s different by first adding a pure sine wave to the track overdrive and then do the same with the master overdrive and the master overdrive act differently. If you ad the track overdrive to a sine wave that wave becomes a square wave due to the added harmonics and that’s just how clipping distortion works on a sine wave. But it’s not the same effect with the master overdrive.
Both overdrives are really nice and you can use them to apply different results. For example, one of the easiest ways to resemble a square wave with the Digitone its just to add the track overdrive to a sine wave.
To my ears the master overdrive offers a distortion that acts differently and that are more aggressive and sounds more gritty than the track overdrive. The master overdrive introduces more severe beats due to the added harmonics than the track overdrive.