Is that right though? I've heard many modern manual cars will cut fuel to the injectors when coasting in gear...
That's why I do the same thing, coast in gear until the revs drop close to 1k or so.
Being in neutral is worse on fuel because the engine has to tick over rather than being dragged along by the car's kinetic energy... and it's better on fuel because you will coast further, as long as you actually need that coasting distance instead of wasting kinetic energy into warm brakes.
Which effect wins depends on the situation... I'd say the higher your speed and the further you can coast, the better to free-wheel it. As soon as you touch the brakes it'd have been better to drag the engine along to avoid that tick-over fuel.
It's why some modern DSGs actually go into neutral when coasting rather than dragging along the engine at high revs, and re-engage some gear if you slightly prod the brakes to utilize engine braking. Current iterations also shut off the engine before fully coming to a stop. Near-future iterations will also shut off the engine at higher speeds, grabbing some hybrid-car-advantages without actually lugging a hybrid's large battery around.
Here's an older one keeping the engine running (spot "Freilauf" in the display, German for free-wheeling):
Near-future PR: