Actually we can go from idle to some maximum power setting called "MIL", and then we jump to max power switching on wep.
With the exception of having WEP switched on, any throttle position will have little negative effect during combat, except fuel consumption. Engine will not overheat at all even running forever at maximum military power. But what we have as MIL was not a safe power setting at all for most fighters. Every engine had what was called max continuous power, usually below than our current MIL power.
I understand that any throttle position above max continuous will start to raise the engine temperature, and the available WEP time should be reduced also.
We can use 190A5 as an example. At sea level, its engine had a max continuous power output of 1365 Hp. 1550 Hp was the normal "climb and combat" power setting (1.32 ata, what we call MIL), but it was limited to 40 mins. 1780 Hp (1.42 ata) was its maximum power output at sea level, but it was limited to 10-15 mins. Flying the 190A5 at MIL power for 20 mins should limit the WEP time to 5 or 7 mins. To effectively cold down the engine, we should reduce power output to 1.20 ata / 2300 rpm or less, not just switching off WEP and keeping MIL (1.32 ata 2400 rpm).
Modeling this in AH would impact the air combat much more than the current fine tuned fuel consumption per power setting.