I have been following that YT channel for a while....unfortunately doesnt have subtitles (for you)....I do understand it though (Serbs are our distant neighbours)
Long story short.....
Stihl 362 MY2014 (video is 4months old...so do the math) came to his service center from a commercial grade user who uses it for cutting firewood for others.....he knows that guy....so he knows that he uses Stihl HP oil exclusively (he is buying material from his service)
It was said that the saw doesnt have power.....that it runs oddly etc. So first he checked sparkplug....and troughout the sparkplug hole he saw that "star" pattern and wrongly asumed that either piston is melting or some foeign metal particles entered into cylinder.....so he pulled its cylinder.
At the end nothing was wrong with P&C unit.....it was its air filter who was not sealing properly and thus letting sawdust into its airsystem (luckily that didnt damaged P&C)
But he was surprised that engine is so spotless and in minth condition after all this usage....and that with mineral Stihl HP
as I said HP is a FB grade oil , appropriate for most 2T applications . I have not witnessed any downside other than its over priced . I have never bought any Manufacturers oil . It's simple economics , why by a marginal product and pay xtra to line the Dealers pockets ?