Supercharging=better gas mileage?

[PARAGON]

Great explanation H2M&W. Now some theory thinking. Assuming both were belt driven, why couldn't a dual charger be made. Granted tuning would be a bitch but in my mind it seems possible. Follow my thinking a little here:

You have the roots mounted on top of the intake providing charge through the use of the twin screw and an intercooler. Off the body of the roots you have a hole/port where the output of the centri charges the air of the roots' body. Have a valve there that opens upon pressure increase from the centri. I guess my question would be, does the roots lose boost as well as efficiency after the extended use and it heats up? I am assuming boost does drop and the centri would be picking up the slack then.

Dialed in, this would keep a charge in the intake during the entire RPM range and maintaining a constantly increasing curve.

Ok, now poke holes in the theory because I am sure someone would have already thought of something like this if it worked.