The way that the parameters work for the "regular" (not notification) LZW31-SN LED is that you have three settings:
- LED bar color (parameter 13)
- LED bar brightness when on (parameter 14)
- LED bar brightness when off (parameter 13)
Looking at Inovelli's driver (I haven't used it; just looking at the code), it appears to modify only parameters 13 and 14 with the child "LED Color" device, so it isn't possible to use it in exactly this way. You can do what it sounds like you don't want to do--set the "off" LED level manually to whatever you want and just leave it there all the time (the color will still change because there aren't separate on/off parameters for that).
Inovelli could modify their driver to provide a way to allow this, but it would involve either a custom command or yet another child device for the "off" level (something I actually played around with on a custom driver I wrote for these but wasn't sure how crazy of an idea that was or wasn't). Presumably they didn't because this matches the way the device parameters work. If you're proficient with Groovy and Hubitat's Z-Wave device model, you could also add it in yourself (e.g., with a custom command on the parent), but that might be more work than you'd want to take on just for this.
