Hi sherib,
A forum search on “Dynasty” (you can just click this) will bring up more information about them including post #5 here which talks about their listings possibly being inaccurate about the density/quality of the foam in their mattresses. It’s not uncommon at all for some of the “race to the bottom” types of retailers who sell based on price only rather than “value” or who take advantage of the lack of knowledge most consumers have about mattresses, to have inaccurate information in their listings, or to make completely unreasonable comparisons with other higher priced mattresses.
You can see the criteria I use for memory foam mattresses in post #10 here and if they don’t meet these I wouldn’t consider them. The knowledge and experience of any online provider to help you make good choices and provide you with accurate information about the mattresses they sell is also a big part of the value of an online purchase because no matter what the cost or “value” of a mattress you buy may be … if it doesn’t match your needs and preferences then it would have little value to you and you would need to return it or exchange it and start all over again (if it’s possible or if the return shipping costs aren’t so high that it’s really not worth it).
Post #12 here has some of the better online memory foam options I’m aware of that would be well worth talking to.
Phoenix