I don't know if I buy the explanation. For a start (255, 255, 243) looks nothing like the pixel he's talking about (it would be pretty much a yellowish white). If what he's saying is true then, without knowing the details of the rounding, anything with (>254, 255, >236) would exhibit the same issue, surely?

It's possible he just dumbed down the explanation for his video but I'm still too scared to make it my wallpaper. :)