Leave the WEP limits alone. Real life, the fluid needed for some WEP was the limiter when the tank ran out. For others it was a warning in a manual based on a general material order to achieve a usable life time for an engine. In all cases something was in place to limit WEP use. In the allied air forces you could be brought up on charges after some point if you had a pattern of using up your engines sooner than reasonably expected with out a sufficient threat to your mission or life. Just like being charged for not taking care of yourself unless you were in combat being shot at, since you were a government issue asset.
And no, our game furballing is not a sufficient threat because our fuel burn shortens our combat duration and our range to the nearest friendly field is often a fast glide away. Otherwise allowing for 200hr merlin boost at 18, or 8hr for a P47, we would be flying around in an old folks version of war thunder.