I'm just going to point out that yes accurate wideband info is ideal but it's not the end all of tuning. I typically use a tailpipe wideband as a suggestion when tuning cars. However my personal car has never ran a wideband. And I run 18psi on pump currently.... Previously I was running up to 24psi on e and never really cared about the slight inaccuracy of the oem O2...
Although in regards to op I appreciate the post! It's good to see more data like this.
I had at one point plotted my lm2 vs a stock O2 and in the 11-12afr range it was fairly close and "good enough" for me at the time.
Rememeber perfect afr isn't everything. Perfect reading simply helps when calibrating maf / ve tables and such.