ESC q calibrate

Could anyone help me please ?
I have a problem with doing ESC calibration
I have done ESC calibrate following this:
Several time and the result is 4 motors don’t spin at the same speed
So that mean calibrate not successful ??

Are there other way to do ESC calibrate??

Anyone help me please thank you.

Step 9: 1. wait for the ESCs to beep to indicate they have registered the maximum PWM

I don’t know wait for how long? then lower the stick to zero

I use 2 batterys 6S = 12S battery

How you making this determination?