Checking timing on a 78 75hp Evinrude

[txbandit44]

I am reading up in the FSM for this motor and the procedure to check the timing pointer setting. I figure before you set the timing you should make sure that mark is right since it is adjustable. WTF? Anyway the procedure says to install a piston stop and adjust it to stop the piston at 26 deg before top dead center. And mark the flywheel. then rotate counter clockwise until it stops and mark it again. The say right in thr middle should be TDC. Since the cylinder fires each time the psiton reached the top. why wouldnt you just stick a rod in the spark plug hole and rotate the flywheel untill the stick pushes out as far as it is going to go and that would be TDC.

Why would you do it the other way?