Measurements never lie, but sometimes they can be an illusion...

[peng]

As class D amps have ultrasonic noise it would be very useful to add some tests in the high frequencies range.
May be a TIM or THD around 10 khz.
Do somebody has an idea?

It may be useful as an extra test, but you can't really hear the harmonics in the ultrasonic range so I think 5 kHz, or up to 9 kHz may be more useful because at least some people can hear the 2nd harmonics at 18 kHz that is within the audible range.