Hi oceanmd,
Post #32 here also includes the specs of some of the layers in their innerspring mattresses that use different densities of polyfoam in different layers. As you can see they are close to the same as the ones you were given (except for the foam that is used in their Eurotop mattresses).
In the case of the mattress you are looking at …
The top quilting layer is lower density 1.2 lb quilting polyfoam but this is there to back the quilting and affect the surface feel or “hand feel” of the mattress and help the cover keep its shape and are very thin so these would not be an issue. The softening of such thin layers would not have a significant effect on the mattress.
The next 2.25" down are 1.5 lbs which is at the lower end of what is commonly referred to as HD polyfoam. They are higher density and more durable than many of the foams that are used in mainstream mattresses (which will often use 1.2 lb or even lower density in their comfort layers). This is a density that I would use cautiously and in thinner layers in a two sided mattress where they can have good durability when used with caution. In a 1 sided mattress I would want to use 1.8 lb density or higher. In addition to this they also use cotton in the layering which will even out the compression of the foam and increase it’s durability. The Innerspring is a firm and high quality knotted offset coil with a good insulator to prevent the foam from sinking in to the coils and even out the surface.
So overall in a two sided mattress in this low budget range I would consider this to be a very good quality and value mattress that will be more durable than it’s competition that is made by larger brands.
I’m have always been impressed at their transparency and willingness to provide this information to their customers who ask (although in most cases they would need to look it up in their “specs book”) and I only wish that all mattress manufacturers were that confident and willing to provide the quality details of what is in their mattress.
Hope this helps 
Phoenix