What exactly does RCn_OPTION 10 (RangeFinder) do?

I’m setting up my first (forward facing) rangefinder for object avoidance and was under the impression I needed to set up a channel with OPTION 10 to enable and disable it.

Yet when testing this in MP, messages say “Rangefinder LOW / MIDDLE / HIGH”. Is that some kind of sensitivity rather than on/off? I couldn’t find anything about this output in the documentation.