Ahh. I get it. Thanks Kalle.
But then, shouldn't the payloads in action:
<action actiontype="File.Write" repeat="1" logic="False"><paramstring>{Path.VC}\huetest.bat&&{1} {3}{2}</paramstring></action>
be ordered {1} {2}{3} ?
The payload range in {3} is obviously not a big deal -- Casmo can just change that from 0 to 255 and delete the phrase "percent".
[Edit: if he wants to increase or decrease, then I guess not 0 to 255, but whatever range makes sense that is not percent-based. Increase by 10, 20, 50, 100, 150, 200 -- whatever, since 120 is approximately 50% brightness etc.]