Michael, that thought hadn't occurred.
But Google has the answer, it's 'No'.
In the UK Octane ratings are by the Research Octane Number (RON). In the US it's Anti Knock Index (AKI).
AKI is an average of the RON and MON rating for the fuel. MON is the Motor Octane Number.
87 AKI = 92 RON
90 AKI = 95 RON
Hmmm so 98 to me is 93 to you in the US, mystery solved. It's amazing what you find on the internet...
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