I guess something like that. In location where I live there is a petrol which rated as 93 but it's a mix with 15 percent bio ethanol and it's a bit cheaper even than 91. So I think 93 octane reached by mixing 91+15% ethanol and now it is rated like 93 octane if you know what I mean.
My question is it better than clean 93 safer stronger?
P.S. I know that E85 (bio ethanol) is not good for rubber seals and things like that.