They are not "overdriving".
To give you an example, if they are using 3w LEDs, in the past they have "under driven" them for heat and longevity. So 3w LEDs at 100% were actually only burning at 2w.
Now, if some LEDs are not running at 100%, it will let you run other LEDs at more than 2w since cumulative heat of all LEDs is lower.
So they have been using 3w LEDs all along. But you used to be limited to 2w at 100%, now you can go up to 150% and run then at 3w if other colors are running at < 2w.
I was just throwing numbers out there to give you the idea. I'm not sure what the controller will actually run them at. I just know that they haven't been running the LEDs at full capacity.