apparently the ECT sensor is a dual sender.

Sends one signal to the PCM and one to your gauge.

Note the apparently.

But it would explain why the fans never came on but your gauge read high.

If possible it would have been interesting to see what a scan tool would have said the ECT was when the gauge read that it was overheating.

My tight control on ECT is because of the lowered fan settings.

Yours is behaving like a stock car should. Replace the ECT sensor (if you havent already) and enjoy.