Found the answer to my own question. Probably should have searched a bit more before posting....
They are apparently to make for easier click count adjustments when only a half turn or less, one way or the other is needed.
Google is my friend.
Thanks for looking!
You cannot wake someone who is pretending to sleep. Stop pretending. Wake up.
Doubt: ...it's the only thing I'm sure of...
-Marsupials: Nature's idea of Concealed-Carry-