Hi Or,
Yes … the link is the same one I linked in my last reply and the information says nothing about the quality, durability, or softness of each layer and has limited usefulness (except to indicate roughly how much soft foam there is in your comfort layers).
The testing guidelines in post #1 here should be helpful.
The pillow thread here has some good information and links to some good resources that should help.
Not only is this possible but quite likely. The mattresses section of the site (starting with the overviews) has a lot of information about this and how different designs and layering are more or less suitable for different sleeping styles and body types. It’s the basis of all mattress theory and design to provide the two basic functions of a mattress which are good pressure relief and good neutral alignment in all your sleeping positions to accommodate the many differences between people.
In general terms the deeper layers or components are all about primary support and alignment. They “stop” the heavier parts of the body and in particular the pelvis from sinking down too far. The upper few inches of the mattress are all about pressure relief in all sleeping positions and side sleepers need thicker and softer, back sleepers are in the middle and stomach sleepers need the thinnest firmest comfort layers of all the sleeping positions because otherwise the risk of sleeping in a swayback position can be quite high. The comfort layers also provide secondary support which is the lighter support that fills in the “gaps” in the sleeping profile (such as the waist on the side and the small of the back when you are on your back) and helps to maintain the natural curvature of the spine. The area in between the top few inches and the deeper support layers are the “transition layer or area” which helps with both.
These comfort, transition, or support layers are also just terminology used for convenience and may not be specific or individual layers of a mattress (see post #2 here). Even with mattresses that have a single layer, the top part of the layer is for pressure relief (forms the pressure relieving cradle), the deeper part of the layer is for primary support (stops the heavier parts of the body from sinking down too far), and the middle part of the layer is the transition area (helps with both). Every individual layer or part of a mattress compresses to different degrees at the same time. With mattresses that have multiple layers, the “support layers” and the “comfort layers” and the “transition” layers have “fuzzy edges” depending on the body type and sleeping positions of the person and how far they sink into the mattress in different areas of their body. In real life every layer of a mattress affects every other layer to different degrees. In other words … the comfort, transition, and support layers of a mattress are really the top, middle, and bottom sections of the mattress even though if there are multiple layers in a mattress the material is chosen with the main purpose of the layer and its position in the mattress in mind.
Don’t forget that “support” is the means and alignment is the goal. “Support” … particularly under the heavier parts of the body such as the pelvis … is important (which is all about the deeper layers) but when you have that then the comfort layers need to “just barely” accommodate the pressure relief needs of the most pressure prone position (usually the side) so that you are as close as possible to the firmer support layers. “Just enough” but no more is the key with pressure relief. This is part of the reason why choosing a mattress based on the cushy kind of “comfort” that people are attracted to in a showroom can often lead to back issues over time.
Comfort is what you feel when you first lie on a mattress … and is mostly about pressure relief.
Support is what you feel when you wake up in the morning … either with or without back pain or discomfort … and is mostly about alignment.
Durability is what you will feel over the years as the foams and other components begin to soften and degrade and this is all about how long a mattress maintains the comfort and support qualities that you need.
Post #6 here may help you visualize what good alignment “looks like”.
There are several “species” or types of soft and firm and the same words are used to describe all of them even though they mean different things and different people may be more sensitive to one or the other. There is the soft/firm that describes the surface “feel” of a mattress or the “hand feel”. There is the soft/firm that describes the upper layers and the pressure relieving ability of the mattress and how well it forms a pressure relieving cradle that re-distributes weight. There is the soft/firm that describes the firmness of the support layers and how far the heavier parts of the body sink down. Finally there is the soft/firm that describes the more subjective overall feel of the mattress. Some people use the same words to describe very different perceptions or the “species” of softness and firmness that they are most sensitive to. All of them are different. So when people talk about the softness or firmness of a mattress … it’s important to know “which” softness or firmness they are talking about (hand feel, pressure relieving softness/firmness, deep support softness/firmness, or overall perception) because the “overall impression” is not really specific enough to know what is happening when you lie on a mattress (although the softness of the comfort layers is probably the one that most people relate to … at least initially).
Phoenix