[b3lha]

I think I see what you're saying: The values in the table are the target Air:Fuel ratio that the ECU is trying to achieve, but because no two engines are exactly the same, especially after 100k miles, the actual ratio of the fuel and air that ends up in the cylinder may not quite match the target. So you measure the actual ratio with a wideband sensor and adjust the values in the map to compensate for the engine's imperfections? Did I get that right?

I find it interesting that applying the formula has flipped the graph upside down. In the raw data, 80 hex is 14.7 (assuming the engine follows the target AFR perfectly). Values higher than 80 indicate more fuel, rich mixture, lower AFR. Values lower than 80 indicate less fuel, lean mixture, higher AFR.