It'd be an on on if you look at the schematic you'll see the 4 positions toggle between different value caps and resistors
SW1.1, 1.2, 1.3 and 1.4 with SW1.1 being the only position that doesn't select between 2 components as you can see either R20 or nothing
Switches are quite difficult to suss on schematics, for me anyway, connections are often left off (pardon the pun), because it's assumed you know