Perfect fuel ratio is 14.7, but your diagram shows 13.8 and 13.4, which means 5-7% of gas doesn't burn, killing O2 sensors, catalytic converter and spark plugs.
I would like to hear story about somebody, who got adjusted ECM and then paid for cat replacement!
Likely absolutely no one...14.7 is indeed stoichiometric where the mixture of fuel and air is 'ideal' for a complete burn of both. 'Perfect' for a complete burn isn't 'perfect' for power and most naturally aspirated engines make the most power safely, and I stress safely as you can go leaner and get more power while risking things like detonation and burnt plug tips, etc., somewhere between 13 to 13.5-ish, give or take. Some will make more power at 12.8 while others might run better at 13.6, it all depends upon the engine and combustion chamber and piston shape, valve placement and valve/cam timing events, etc.
I played with tuning my Katana between 13.2 and 13.5. Most guys who are going to the trouble of tuning their bike are also doing an exhaust, which usually deletes the cat anyway, but a 13.5 ratio isn't going to kill a catalytic converter. If you look at factory tuned bikes or cars they never run at a perfect 14.7 either, which goes into the whole open vs. closed-loop discussion, etc.
Regardless, I have my Lightning tuned to run 11.8 at full throttle since it's supercharged and they usually tend to run them far richer than an N/A motor for safety reasons. It's got cats and I've never had an issue with them, nor do I see them needing a replacement as long as I own the truck.
Now leaded gas, as some guys have run previously at the strip for the octane rating and to ward off detonation, will foul and kill a cat in relatively short order.