In the filter box putting something like [50118.238]=1 will make it only use the data when commanded lambda = 1
Putting something like [50118.238]<1 will make it only use the data when commanded lambda is richer than 1
So.. try those and see what happens
You really need to be looking at charts where you can put commanded AFR and actual AFR on top of each other so you can see what's going on