WOT throttle is usually anything over 80%, regardless of load or how fast the "pedal hits the metal" (I like that...LOL!!). This is the point that the ECU goes into "open-loop" and reverts to the basic programming...start-up, cold-running, and WOT. Basically the stuff you can adjust on any handheld tuner. Once the ECU senses that the engine is warm (closed-loop), it uses all the emissions sensors to adjust long and short fuel trims and to maintain efficeint operation. You are right that WOT overrides everything, because it "locks out" the sensor information and looks specifically at the predetermined tune values. That's why if you were to say, adjust your spark advance when it is 30* ambient and dry and it works great, at 70* with high humidity, it will not run the same at WOT, possibly to the point of causing damage. The ECU no longer cares about what the air conditions are, it goes to the basic programming (for 30* and dry in this example). Part-throttle, it affects nothing because the ECU is in closed-loop, using the info it's getting from the MAF, O2s, etc.
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