I think I saw somewhere about ethenol versus non-ethonal gas use I recently had Mike at Suzuki city Biloxi Ms. replace cam tentioner and chain it was streatched I meassured it myself and had head plug leak fixxed. Keeping track of my mpg I started at 44mpg 46mpg using high octain with the ethonal and just got 50.5 mpg using low octain non-ethnol. Am going 12 miles one way to from work/home usually around 40mph in third/fourth gear and once or twice for twelve miles going other way to friends house doing 70 on supper slab. Have 18inch slipstreemer for winter riding on. Which feul is better for stock bike no mechanical mods to bike yet. Plan on spacer and idle playing with idea of exhaust. Chain and tentioner at 21700 by the way.

Everyone gets less mileage with ethanol and ethanol-gasoline blends because it produces less power per volume, which causes drivers to push on the throttle more and riders to twist the throttle more.

Best to avoid the ethanol if you can.  It absorbs water, helps to rust out steel gas tanks and degrades the fuel faster.  Before storage try to top up with gas containing no ethanol.

MPG may be less, but on a trip 3 yrs ago, I burned both kinds across the country,  and there was no noticeable difference in my Motor Home getting 9.5 mpg.
A couple tenths less ?? Maybe, but it varies that much from tank to tank anyway.