Agree, that’s a lot of IAB for dual carbs. Sounds like it’s pretty good on cruise. what’s the MAB size? O2 meters are pretty accurate when calibrated. OEM wouldn’t use them if they were that bad. Pump premium and 110 are usually pretty good in the ranges I listed. When you get into oxygenated fuels and such things change. I do agree though you have to tune the engine for what it likes. I still read plugs and jet for MPH but, I find the 02 meter puts me right about where I need to be on most applications I work on. I have a pretty good feel for it, I play with it enough.