I seldom compare what the WBO2 is showing vs. what TunerPro RT is showing. I spend 99.98% of my time working with Excel spreadsheet.

Sometimes I pour some gas into the throttle body to verify lean WBO2 readings are really lean. Pouring gas into the throttle body will temporarily make the engine run rich and the WBO2 will temporarily show rich AFR's.

I wonder if blowing compressed air into the throttle body (throttle blades closed) will cause a rich running engine to temporarily run lean. Seems logical, but I've never tried blowing compressed air into a rich running engine.