Well we did notice the dual widebands were nearly identical bank to bank under all conditions BUT WOT. Under WOT the Driver's bank was a full point richer than the Passenger side. I think its just a quirk of the dual plane design and I too have run out of time to explore it further. We had to richen this up a little and it seemed to make a touch more power everywhere but mainly to keep it a little safer for the end user. My carb guy is great and set these 600's up ahead of time so secondary fuel adjustments were easy. J.Rob