Fuel is flowing to the engine while coasting.
I've already switched-off the engine while coasting and you can defenitely feel the difference in what concerns deccelaration.
After the engine is switched-off the car starts to loose speed at a higher rate than with the engine switched-on. It looks like coasting with a car without injection (does any of you remeber?)
Now, what I don't know is the amount of fuel that's going in (more or less than iddling conditions)
This experiment was not perfomed in a Mercedes, though. It was an Honda, with a Bosch injection system, so I think things would be pretty much the same in a MB. (Remeber: this should not be performed unless you kbow EXACTLY what you are doing since brakes will fade away, steering wheel could lock itself, ...