CL300, I would be interested to know from where you got, or how you "derived", the "derived data" for a slope of 18% in the Citation that you operated into Corchavel.
Is it published by Cessna? Would you have a copy to show us please? Which sim had the software capable of accurately extrapolating to 18% slope, when no data of this nature was ever entered into its original logic?
On another point, I am inclined to disagree that the real issue is landing. My experience here, and other similar places, is that most pilots adjust quite easily. Sure the concept of adding power to roll up the hill is a bit alien, but a gentle reminder is all that is needed to avoid embarrassment.