Hi Bob<Martin,
They are one of very few manufacturers that provide the choice between them but most people wouldn’t be able to tell the difference so you would need to trust that what you ordered is what they provided. This is one of the reasons that it’s always a good idea to make sure you are dealing with a reliable and reputable supplier such as SleepEZ so that you can have confidence that what you order is the same as what they send to you.
I don’t know of any twin mattresses on the SleepEz site that use 100% natural Talalay that are only $399 in twin (or any Savvy Rest mattresses that are $699) so I’m assuming you mean a topper?
If this is the case and they both contain the same thickness, type, and blend of latex than the only difference between them would be any differences in the cover.
There really isn’t a specific answer to why one manufacturer sells very similar products for higher prices since consumers don’t have access to the business financials that determines the cost of their products. One of the differences may be that SleepEZ is factory direct while Savvy Rest sells through retailers but there could be many other reasons as well and you can see some comments about the difference in prices in post #6 here.
Phoenix