For a supercharger, you are constantly in boost. It doesn't matter if it's partial throttle or wide open throttle.

Turbocharger is different.

 

^ Nope.
True the turbine is always spinning but it does on a turbo as well. And just because it is spinning does not mean that it is creating excess pressure. With the S/C the bpv bleeds in partial boost situations so by my gauge at the TB I only boost at wot or almost wot starting around 3k. Most of the time unless I really floor it I only boost 1 or 2lbs in situations like getting on the highway quickly. ...and thats with the 9.5lb pulley.

If you drive lightly the fuel consumption is similar to the NA tC and the only difference you'll see is the price of premium over regular.

 

1 or 2 lbs of boost is still more than vacuum.

 

^ lol.
But thats when I accelerate quickly but not quite at 100% full wot (maybe 95%).
Under 'normal' defensive driving conditions and light to average acceleration and I can still get close to the average fuel consumption for a NA tC and never get into boost.