The current Super Champ X2 is a 15 watt amp according to the owners manual. Mine was made in November 2018.
I do not consider the modern hybrid Super Champ x,y,z,,XD whatever suffix tobe in the same class as a handwired, all-tube Super Champ from 1982-1985. When I talk about those modern amps with solid state preamps and digital effects, I use the suffix. There is only one Super Champ. It is an 18 watt amp. If that video says the Super ?Champ is a 15 watt amp, then that is why I made the observation that it is an 18 watt amp. Anyone who wants to be accurate about amp models needs to use whatever names, numbers, letters etc denote that specific model, imho and ime. Otherwise confusion reigns....but then, confusion seems to be the mode of the times, eh?