Ben's chart is (I hope this is right) his approximation based on his experience and education as to when you actually reach breakpoint.

Importantly, it also protects vinyl liners from potential fading at those high levels. You have no vinyl to protect. Raising your Cl to 30 absolutely insures that you reach breakpoint...allowing your Cl to be more effective. It will come down to normal levels as the Sun and new organics continue to consume it.

I see no downside to shock level Cl in the low 30's for a gunite or Fibreglas pool.

DISCLAIMER: This opinion is based entirely on anecdotal evidence and, given the intelligence level of the opinionator, I would take it with a small grain of salt.