1290 mileage modes

I was talking to a tourist from British Columbia at the petrol station. He says he runs his S1000RR in rain mode while droning along the freeways to save fuel. He says he needs not all the horsepower and it saves him a load in fuel costs. Has anyone done any comparisons on mileage changes from the mode switch?
I would like full tank full differences from the long haul journeys and not short jaunts. It would show how truly far the bike could go if needed.

At one point on my trip to europe a few weeks ago we had to do a bit of mile crunching which involved quite a few motorways. I had filled the tank, brimmed it and stayed in "sport" mode. The bike registered 319miles, 57.7mpg, 0 fuel range...Then filled up!
I was pretty shocked and fookin impressed with that! So i would assume if you went to Street or Rain mode then you might squeeze some more out of it.