You are misunderstanding what does the wear and tear. It's not the thrust produced. it's the temperature (ITT TGT EGT).
We derate to reduce the ITT. Work done is ITT not thrust. Thrust is density X ITT.
So when I ask for "full take off thrust" at a temperature above the flat rated temperature of your engine (typically isa +15 but not always) then the fadec looks in it's little table to see what N1 would normally be required and sets it.
As the N1 required will be reducing with temperature in this area above flat rated temp then the work done to produce that N1 will be less than the work required to achieve the N1 for the real temperature.
Less N1 will require less work and therefore less ITT.
Note:
Due to the density difference between real and assumed temperatures the actual N1 for assumed temperature will always be lower than the N1 required if the real temp = the assumed temp used.