This is true, and all of this I know very well. However that isn't what I was addressing.
Which is just to be cautious.
Some people may take that advice without taking it to a dealer when it could very potentially be a serious fault that could cause more damage. Though it's something that would surely be covered should the worse happen, you have to ask yourself do you need that hassle for the sake of treating any sudden coolant loss as a
problem.
It's just as likely that it isn't a huge issue and it is a simple air lock in the system as has been theorized.
But the official company line and what to do should you have any problems with the coolant system is what's in the manual.
That's the only point I was making.
Is it worth second guessing a potentially serious issue.
If you read what dw911 says he also points out the importance of taking it to a dealer to investigate a sudden drop in coolant. So I'm just reiterating his own point.