Tuning Maf for fueling

I have a Mitsubishi EVO 3 using Ecm link and I'm trying to get target afr to match actual afr. The Maf has hz as scaling and percentage changes as hz increase or decrease .How do you tune this for fueling or is there a formula for the percentage changes.example at 1600hz measures af ratio is 9.1 gasoline and desired is 11.. I converted 9.1 to 0.63 lambda and 11.1 0.75 lambda.which is 12 % to rich so do I just do 12% adjustment at the 1600 Hz range?

Personally do it by estimations at 2D graph for wot afr .

Process taking 2 adjustments to achive my afr target !