I think FL has extended late closure for intake valves. This will improve low load fuel economy. But I can't be sure.
As you say, it looks like low load, low speed cruising should favour CVT. But again, it's difficult to find any published efficiency numbers for the two drive trains.
It would be interesting if they allowed other folks to attend the pre-event briefing just to pick up tips for driving efficiently. The best people to learn it from are Nissan. They know how the engines and transmissions are set up and where the sweet spots are.
Why would FL be getting more fuel economy?
Better ECU/TCU tuning?
Also, i thought CVT is more fuel efficient then 4AT, cruising rpm of CVT is lower isn't it? 100km/h on 4AT is 2.5k rpm, while its just 2k rpm on CVT.