Since SSG is so desperate for the numbers, I'll give him one a from a now defunct operator... got it from the guy who had worked there... accuracy not guaranteed. I can't give the exact numbers for obvious reasons.
Numbers for the 733/4/5, average hour to cycle ratio 1h10m, 10 cycles a day average. Destinations are all <2500m runway (mostly <100ft elev, ISA+15C) except for 5 airports with 3000m - 3600m runways.
Derate take off & derate climb policy = about 50USD per cycle. at 10 cycles a day, equivalent to 100k - 150k USD per year.
Derate take off only would save about 30USD per cycle (less fuel and engine wear, whereas the derated climb expends just a little bit more fuel, but significantly reduces engine wear).