in the second set of plots, are you running more advance?
It seems like what was mentioned originally can be true, and that a slightly leaner (~11.5:1) AFR seems to make (slightly) more peak torque.
However I think there is a lot more at play here on modern engines with AVCS and variable ignition timing. It's not like the earlier days of EFI where more values were static, and the AFR was really your only way to generate power.
But I'm probably just stating the obvious
Awesome thread though!