I can't speak for someone else, but I suspect the red text above is a mis-type. The secured container section does not require one to either have or not have a CHP, nor does it require one to stay in the car.
ETA: Hmm, thinking more about this... maybe he is right... the secured container provision does only address while one is in the car, and once you exit, then I believe his point is that you revert back to the other sections which require the firearm to be unloaded.
ETA(2): The secure container text says: "10. Any person who may lawfully possess a firearm and is carrying a handgun while in a personal, private motor vehicle or vessel and such handgun is secured in a container or compartment in the vehicle or vessel;"
So if you are not "while in a ... motor vehicle", the exception is not met. And there are no other code sections which allow you to store a loaded firearm in a car on school grounds... at least none that I am aware of!
TFred