This would come in handy if you want to raise or lower certain channels relative to their current value with a submaster.
E.g.: I have a drum-solo sub, that raises the drummer's frontlight to full, while bringing all other musicians down by 50 percent, relative to their current values. The benefit to storing all other spots to 25 in the sub is, that if some of the spots are currently off, they stay off.
My current workaround is a one-step absolute effect, that does this. But relative palettes, or a relative intensity syntax would be more convenient.
