ADV8005 HDMI TX output resolution

Hi

I want to know when ADV8005 memory mode is set to YCbCr-12b-10b-10b

And HDMI TX color depth is set to 30bit, (10bit x 3)

What is the max output level will be? 1020 or 1023?

It seems the max value is force to 1020?

I try to use contrast to set to max level, it still 1020 not 1023?

I want to confirm if ADV8005 max level is 1020 output?

Thanks

Ken