Good question. Two things here.
1: I've been looking at a bunch of the "suggested" shaft stiffness by distance and, depending on manufacturer, I should be hitting a extra stiff shaft.
2: I can be a bit wild at times off the tee. When I hit a regular shaft club I can get REALLY squirrely, regardless of head. If I get more accurate moving from regular to stiff, then would I still get even more accurate moving from stiff to extra stiff? I don't know.
Or, is the answer "Chill out and get consistent with the Ping. It's good enough?"