Um... wrong. Do you know what an octane rating means? Higher octane=harder to ignite. Same ignition/compression with fuel that is harder to ignite=less efficient burn. Less efficient burn=lower performance.What kind of crack are you smoking? There is no detrimental effects of having more octane, only less. The only down side is you threw away your money and didn't benefit from it, but the engine will never give you less performance from increases in pump rated octane.
Dont believe me? Try putting some race fuel in your bike and start it on a cold day.
Of course an octane thats too low=detonation which is obviously the greater of 2 evils.