Hi Moose0721,
Within a reasonable “margin of error” yes (and there are actually more than 3 different types of foam used in the iComfort lineup). Gel memory foam itself though has some other issues based on the different uses and methods of infusion used to incorporate it into memory foam “chemistry” itself. The “gel powder” or “beads” which is added to memory foam is not without its challenges and there is a great deal of controversy and differences of opinions about gel memory foam itself and its different methods of manufacture. Gel is heavier than memory foam and so can “artificially” increase the density of the memory foam layer. Infusing different percentages of gel into memory foam can increase the apparent density of the memory foam used as a “base”. Different methods of production and chemistry will also increase or decrease the likelihood of the gel “separating” from the memory foam as well and decrease or increase its strength. There are many technical issues here and these have been the subject of many conversations I have had. “Gel memory foam” is not a single material and has many variations.
This is based on a misunderstanding of what makes a memory foam mattress feel firm or soft. Memory foam itself is the least supportive of all foams which is why it requires a firmer support layer underneath it. Having 7" of memory foam in the top of a mattress … no matter what type or density of memory foam it is … is a recipe for back issues. This is the reason for suggestion #4 in the memory foam guidelines I linked to in my last reply. Using “unknown” memory foam also increases the odds of some of the “memory foam” issues that you can read about all around the web. I personally wouldn’t take the health risks of using unknown and untested memory foam in my mattress.
I understand the desire not to make a “mistake” when you are spending money on a purchase which can have such a big effect on the quality of both your sleeping and waking life. This is why the guidelines I have written and suggested … while not absolute or “perfect” … will help you dramatically increase your odds of making better choices.
Phoenix