You didn't ask that.
What you asked was an open ended question that inferred a dispute with the recommended fuel requirement. I attempted to address the requirement.
Your original question that I replied to made no mention of difference in American and European fuels. I can go back and get your original post if you would like ...
You asked, for my opinion on the recommended fuel. My recommendation is, use what they recommend.
If there is a difference in US and European markets then the recommendation(s) will be tailored to the market. They will not give european specs for fuel consumed in USA cars. Where they list specs from different markets, they will list the appropriate market's spec first, then give the other market's spec in parenthesis, ie: 5 gallons (20 liters), 1 jinch (25.4mm) 91 Octane (95 RON) -- or whatever the correlation between octane and RON is.
Put in what they suggest ...