Hi thunderfingers,
Based on their cost of materials then the $600 difference would be worth it (in most cases the margins on the mattress lineup of the same manufacturer would be similar throughout the lineup although they may be a little higher in the higher price ranges) and there may be other differences besides just their cooling abilities (such as durability) but I don’t know of any specific data that compares them (or any mattress to another one for that matter). If it exists or the foam manufacturer has any more technical information then they would be able to provide it to you. What I do know is that it incorporates all three cooling technologies in the same material (thermal conductive gel, phase change gel, and high breathability). There is more about these in post #9 here.
Post #2 here also has more information about the many variables that can affect the sleeping temperature of a mattress that may also be helpful.
Phoenix