I can use `Channel @ +/- Level Enter` to modify a channel up say 20 points from wherever it currently is, I think submasters should be able to use the same syntax.
As part of my break macro I want to automatically glow the house lights, but the best I can do is `Sub 1 @ 20` - if the sub is above 20 I am now decreasing the brightness. There are lots of reasons this could be useful, but that's the one I most frequently run into.
