Tas,
You may or may not know our cars do not inject fuel when coasting in gear (it's almost all returned to the tank). Most TDIClubbers consider coasting in gear to be more efficient than coasting in neutral. I tend to believe it's more sensible than coasting with the engine off since the steering, brakes, and even AC (yes, I cave in 100* heat) will function normally.
Oh, check out this photo taken while coasting several miles down to 1000 feet from 5400 feet:
Looking at IAT and EGT, you might conclude there is no combustion taking place since EGTs are only about 40* above ambient temp. I've never seen my EGT so low unless the car has sat overnight.
Take Care,
Scott