Erratic AFR's at the track?

Just wondering if anybody esle might have a little insight on what I'm experiencing at the track with regards to erratic AFR's. On the street I'm getting very stable AFR's and my LTFT's sit anywhere from 0-5%, WOT is very solid and follows commanded AFR's wonderfully. Now at the track I was using two tunes, one for N/A and one for N2O which was derrived from the N/A tune (timing reduction and a richer commanded AFR).

This issue is this, I arrive at the track and after letting the car sit for maybe 45mins I make a pass, AFR's are dead on and the car runs great. The ECT recorded at the start of the pass was 84*C, IAT 86*F. Later on as more cars get the to track and the wait time inline increases, I make passes with the ECT sitting at approx. 90*C (194*F) and IAT's at 100*F and higher... and alas the AFR's are anywhere from .5 to .8 higher than commanded. :doh2:

Now I've gone through the cal and I don't see anything specific to mixture correction for IAT (I do have IAT/ECT blending enabled but the amount of control seems extremley small), something I might be missing? BTW I'm running w/ the MAF, no SD issues here which only add to the frustration! On the way home with cooler stabilized temps I took some more samples, again the AFR was dead nuts on, the only difference I keep going back to is the higher ECT/IAT but shouldn't the MAF be correcting for this? As always I do appreiciate the input gentlemen :cheers:

EDIT: I've included both passes in question, 1st was the first run of the evening, note the relativley cool temps, the later is the 4th pass of the evening, note the starting ECT/IAT.. seems about the only difference I can see!