"ECO" has little to do with vehicle economy except perhaps as a psychological factor. Fortunately it is useful in another way.
Unlike some folks I much prefer the throttle mapping in ECO; it's much easier to drive smoothly in traffic. The increased "pedal resolution" allows finer speed control in normal driving. Contrary to some opinions I find I can always have as much power as I want, it's must a matter of moving the pedal. I.e., power is not restricted in ECO mode, it just comes later in the pedal arc. It doesn't make the car less powerful nor does it make it more "economical"; both of those things continue to be determined by your right foot.
The only time I switch out of ECO is if I want maximum heating/cooling when entering the car as ECO limits the power consumption of HVAC. Even this is a false economy, as you will ultimately add or reject the same amount of heat to/from the cabin; it will just take longer in ECO mode. HVAC economy is controlled by temperature selection, not by the rate of change used in achieving it.
Unfortunately, I have found that Tesla's "Chill Mode" does in fact de-tune the power across the entire throttle map, which I find quite stupid and while I'm not always a fan of Nissan engineering choices, they look brilliant here by comparison.
I noticed you're still working with polymers.