Netgear D6400 Seamless Rate Adaptation (SRA)

Hi

I am currently on NBN FTTN had no problems up until recently, we have had a technician over to our house to check the lines and he said everything was fine.

My ISP has reccomended we change Seamless Rate Adaptation from Automatic to Dynamic, i cant seem to find anywhere in the settings to change this.

Is anyone able to help with this?