They are what are usually thought of as the '2nd' set of holes, to oil the pushrod cup through the matching hole in the pushrod end of the rocker. I've not seen one like the OP posted on the right of his pix, where the shaft was lacking a '1st' set of holes pointing downward in the usual direction.
My 273 adjustable shafts have both sets of holes. (Plus banana groove). I can't explain all the varieties of these shafts.... maybe some for 2BBL and some for 4 BBL???
