Why the commutation delay doesn't work

Greetings,

I generate the project using 

To control the bldc motor with hall sensors interface. The configuration is as below:

Refer to TIM4, which is set as the hall sensor interface, the detail configuration is as below:

Refer to TIM1, which is set as the PWM-generated interface, the detail configuration is as below:

After my debug, the motor can be driven. But I found the commutation delay doesn't work at all. So can anyone explain what the commutation delay means? Which event would affected by this delay setting? Why this delay doesn't work? I measured between Hall sensor input and TIM1_TRG_COM_TIM11_IRQHandler(), and I also measured between 

TIM1_TRG_COM_TIM11_IRQHandler() and HAL_TIMEx_CommutationCallback(). No delay is related to this setting.

B.R.

Jason