Right, it's still putting oil vapor back into the cylinder instead of air, thus decreasing the effiency of the gasoline burn.
All of this is an emissions control which while reducing emissions also reduces MPG causing more fuel to be burnt creating more emissions per tank... I don't know if it reduces the emissions enough to compensate for having to burn more fuel.
'07 Jeep Grand Cherokee 3.0L Mercedes CRD 2wd 110k miles and counting Murdered Out - Elephant Hose - Dashhawk - Powdercoat - "CAI"
'07 Fiat 2500 Dually Highly Modified