Why do men have nipples? I think it's basically the same reason. Easier manufacturing...
But if it was like that wouldn't it also have a pen?
It seems the best guess is that they started including pin holes on both types of scales around 2006-2007 then...?
I think Bill used that slot once to put in an addition set of modded tweezers. If I can find the pics I'll post them here.
as you can see it's ground down shorter to fit in the smaller/diagonal slot.and it was made pointy.