I have made some progress. Using the default 0x84 for PWMFrequenceSet I can get different frequencies, but only a few useful ones:
PWMFrequenceSet MotorPWMFrequenceSet Frequency
0x84 0x00 30.12 Hz
0x84 0x01 1.923 kHz
0x84 0x02 250 Hz
0x84 0x03 30.12 Hz
0x84 0x04 7.5 Hz
What is the absolute maximum frequency the the PWM Motor Driver supports? I need 25 ~KHz. The 1.923 KHz makes too much noise.