I'm pretty sure that in closed loop the ECU is trying to correct to the Air/Fuel ratio table not the fuel map.
If you have the correction set at 20% it will correct a lot more then at 5%
You use the wide band to dial in your base map. With the higher percentage. Then as you fine tune the fuel map by reading logs and overlaying them on the fuel table and adjusting the cells up or down. You back the percentage down so if the wide band goes out you don't burn up the motor.