The best way to look at PWM and MPPT is to just use Ohms LAW. Here is a down to earth, easy to understand video that uses Ohms Law, with the numbers.
You can then look at videos and read about the PWM and MPPT controllers and know exactly when they are pulling your leg.
The basic (BIG) difference is that PWM uses the Amps output of the SOLAR panel and MPPT uses the Watts output of the SOLAR panel. That is how they say that there is a 30% difference, in my tests it was 24.xx% difference (SUN Light intensity, or it probably would have been close to the 30%, and of course there is internal circuit loss). You will see it in the Ohms Law numbers.
He did mess up on a few terms, but the numbers are correct. They can say what they want, or argue till they are blue in the face.... but you can not change the laws of nature.
Shade kills the output of the SOLAR panels.
Don
https://www.youtube.com/watch?v=UhWuT81OW2o