What they did there is exactly the type of measurement I warned for in my post you quoted ... "I checked this with an alternate method, comparing the open-circuit voltage vs. the voltage when loaded with 4 ohms, and got the same result."
There's always a chance something's wrong, but how strong do you think that chance is when talking about technically the best amplifier the world, made by one of the most respected companies in the industry? Do you have any idea what went into designing this amp? In this case I would be a bit more hesitant with drawing conclusions from nondisclosed and non peer reviewed measurements from a Hifi magazine.
