Baron,you say
"The lower the temperature the lower the TAS required for a given CAS, TAS requires thrust. Less thrust required for straight and level means a surplus of thrust."
Not sure what you mean, did you leave a word out?
We're talking minimum drag, so any change in TAS will mean more thrust is required, whether it's an increase or decrease in tas.
There will be no case of "less thrust required", since you already at minimum drag.
I thought my argument was very logical. Is there any sentence you disagree with? Just trying to explain this paradox, that's all. If I'm wrong, belieive me, I'll be the first to agree.
thanks, Hawk37