Additionally, isn't the specific fuel consumption (ie kg/hr per N of thrust) improved at higher engine temperatures?
One of the main reasons jet engines have become more and more efficient over the last 60 years is due to the development of materials which can withstand higher EGTs, thus leading to improved thermodynamic efficiency of the engine.
Therefore, if you aren't running an engine as hot (ie high EGT/high thrust) as you can, you are sacrificing a degree of fuel efficiency, even though it it might actually be only a small amount of fuel wasted.
Anyone else comment on the validity or otherwise of that lot? University was a long time ago...
Of course, other factors do come into play in the real world: engine maintenance costs being the major one.