Do you have a way to see air inlet temp? I bet it is much higher on a hot lap and the inlet sensor is also likely to respond pretty slow. It would be interesting to see if you could make a resistor that plugged in and locked the inlet air temp to a single number.

I moved my Barracuda over to a Rife brand inlet temp sensor because they respond very quickly. My car picks up under hood air from the hole in the hood at low speed and idle. So I leave the line with a higher than ambient inlet temp, sometimes as much as 30-60*. The original GM style inlet temp sensor is right at the top of the throttle body. With the GM sensor I start the run over ambient and it took almost the entire run for the sensor to read ambient again. With the Rife sensor it reads ambient almost immediately after I mash the throttle. That helped smooth out my tuning some because the slow response time was messing with the inlet air temp correction. I might have gained a few hundredths from this but for sure gained more accurate data. I am sure an OEM with border line safe compression ratios pulls timing and throttle response with higher inlet temps.