I don't have the reflash, yet, but ave been running 89 instead of 87 since getting the bike. The only thing done for the engine is Cobra slip-on's, K&N air filter and NGK Iridium plugs. It runs stronger with the new plugs. The OEM plugs looked great with about 5,500 miles on them.
the 89 octane fuel is less than a dime difference right now, so just got used to using it and always ad the recommended amount of Sta-bil fuel stabilizer. I use it in everything that has an engine and never had a fuel problem since, including lawn mowers, pressure washers, generators, etc. I use it like insurance, you never know when something might happen that would prevent you from draining the fuel, etc. There have been occasions that I could not go out and use the power tools for extended periods of time, up to a few years and they have never had a problem starting back up like the day they were left