Hi EZ4HZ,
Most of the minor foam density increments are more about marketing than anything else. It’s similar to one manufacturer claiming that “our mattress has coil count of 1000” and another one says that “our mattress has a coil count of 1020 so it’s better” when these types of single specs and minor differences taken in isolation are mostly meaningless.
You can see some of Novosbed’s comments about the same issue on their blog here.
Post #7 here and post #4 here also includes some comments about the same issue.
Phoenix