My thoughts on the matter.
The company went out of there way to copy and paste Auralex's numbers as if they actually tested it. That should if for no other reason give someone reason to think about what kind of company they are. Companies like mine (GIK) spend a great deal of time/money researching, testing and educating to make sure our customers understand what they are buying and how to use it.
Second, Ethan tested there product in a test lab. Lab numbers don't lye.
Now with all of that said I bet that if you used some of the 3" foam to tame some of the high end it might just work (so do packing blankets), but for the low end that is another story.