pushrod length/measuring question

I guess I’ve been checking pushrod length wrong for 20 plus years now ! I’ve never seen or heard of any of this mess in this thread ! Zero lash , make the rocker arm make contact on the valve in the center of the valve, through out the travel of the rocker arm ! When that happens pull out your adjustable pushrod and measure it ! Order the pushrod that is that length ! 20 plus years of doing that very thing ! Never had a problem ! Obviously, I have a lot to learn on measuring pushrod length