rocker arm adjusment Plymouth

I noticed this a long time ago but never said anything but now I think I will. Why is it on the Mopar valve adjusting chart when you start with #1 being at TDC firing it does not show adjusting #1 but #2in & #8ex? Is it because mopar wants the lifter on the absolute heal of the cam and not just the base circle, and has anyone found a difference in their valve adjustment this way. I adjust my valves like Mrmopartech & perfacar with each cylinder at TDC.