[RustyLugNut]

Old Jupiter,

Your assessment is entirely correct. However, there is one area extra EGR can be beneficial to overall power and economy. IF the torque output at cruise can be maintained with increased EGR and the same fuel load and the consequently greater throttle opening, the pumping losses at cruise can be reduced. This is after all one of the advantages of the diesel engine over the spark ignition engine.

Running an engine in lean burn can provide much the same effect.