I'm back again, continuing my quest for MPGs...
One topic I had seen on the web was to lower the O2 switching voltage from 450mV to trick the ecu into thinking stoich is actually leaner than reality in order to run a leaner mixture in closed loop. After setting all the values in the table to 400mV, it seems like it's working (don't have wideband to verify yet) in closed loop, but something else interesting I've noticed is that now when I use the override AFR and set it to 18:1 for example in my manual lean cruise approximation, it seems like it's using more fuel, or in other words, not leaning the mixture out as much as it did when I had the swing voltages set to the factory 450mV. Again, I apologize for not having a wideband to confirm this, but under the same circumstances, 18:1 commanded AFR today is using more inj bpw and the narrowband o2 values aren't getting as low as they used to when the swing voltage was factory. Does this make sense?

Also, if I wanted to make the commanded AFR settings more permanent, I would need to go into the open loop AFR table and overwrite the 14.7 values with whatever leaner numbers I want, is that also correct?