His vids are long because he's trying to provide all of the details without his results being or appearing swayed. I used to watch all of the way through many years ago (discovered him way back on his second video about Seafoam) but find myself skipping around these days.
Many other factors need to taken into consideration. He claims to be using cold but what is the cold temperature he's using? Manufactures consider cold anywhere between 75F-90F. If his temps are below that, it's going to greatly impact results, especially with enzymes cocktails used in todays detergent.
Some detergents work better in different temps. One detergent may score mediocre or poor in cold yet score high in warm or hot temps. He's also using very low water levels which is much more aggressive, especially in a DD. A full or near full load will provide better accuracy as most people aren't doing very small loads of laundry, especially in a fabric destroying washer.