If you keep your foot in it until you can literally feel the power falling off you are revving it far past where you should be shifting and just beating your engine for no reason.
You're right, I shoulda mentioned take your foot out of it when the Gs drop, don't wait to see if the Gs will go back up. Lol
I bet there's lotsa folks shifting well above their optimum RPM , as you mention, abusing their engine, simply because they THINK they're still accelerating.
G-meter is a simple avail tool that folks can use, and avoid an expensive Dyno.