Actually, the color "Amber" of the four channels you referred to are not yet supported by rekordbox lighting. The channels with (*2) at the end are not supported as shown below.
rekordbox lighting engineers would like to ask you the reasons why you need to use the amber color. They assume you can control channels only with the RGB colors specified by rekordbox. They would like to ask you what you would like to do specifically by controlling the Amber channels.