If you are tootling along at 40 km/h with a feather pedal your trans will be in overdrive, if you floor the accelerator at this point your transmission will downshift to 2 and accelerate quick. Keep it pressed full and shifts will only occur at redline.
There is no need to get ECU fizooliyat here, even in carburettor cars with no ECU, the transmissions behaved like this, they were fully hydraulic and their shifts were governed by the delicate balance between the kick down cable pressure and governor pressure.
Newer transmissions are ECU controlled to fine tune the shift points, the kickdown cable is removed and the TPS is doing its job, the speed governor is removed because the VSS is doing its job, shifts are electronically controlled by solenoids.
Both kinds have 95% same driving experience.