Sorry of you took offense but I
understood what you we're asking
that's exactly why I quoted the manual
and the page number.

It explains all the controls and say's
that the serrated dial adjust the sensitivity
of the rain sensor when the lever is
in position 1.

The only way you will notice any difference
is if it is raining, and how hard it is raining.
There are a number of positions that can be
used with the serrated dial and one must try
each position with the serrated dial while it's
raining to notice the difference.

The sensitivity and the interval of the wipe is
determined by how much rain is seen by the
sensor. It isn't something you or I can determine
or measure. The rain sensor does it electronically.

__________________
"What you hear in a great jazz band is the sound of democracy. “The jazz band works best when participation is shaped by intelligent communication.”
Harmony happens whenever different parts get to form a whole by means of congruity, concord, symetry, consistency, conformity, correspondence, agreement, accord, unity, consonance…….