Hidden fan setting on 2006 CR-V?

The fan control knob on a 2006 CR-V can be pried off (I was cleaning up
some gunk from a soda spill, if you are curious why I pried it off).
The knob has some plastic fingers, irregularly spaced, that engage slots
in the rotary switch itself. The irregular spacing makes it so that
there is only one way to put the knob on.

Now here is the interesting part. If you put the knob on, but do not
push it down all the way, you'll find that there is one more position it
can turn to, counterclockwise from the "OFF" position. When the knob is
pushed down all the way, it appears that one of the fingers is deep
enough to hit something put down there to stop the switch from being
turned past off to this extra position.

Anyone know what this extra position does? It appeared to be the same
as "OFF". Did they simply use a rotary switch that had an extra
position they did not need, so they left it unused and blocked the know
so you wouldn't see it?