Will them being always stored compressed decrease their temperature rating?

Here is a link http://www.amazon.com/Ledge-Sports-FeatherLite-Compact-Sleeping/dp/B007U51UAW/ref=cm_cr_pr_pb_t

The features listed are as follows:

Size: 84 inches X 32 inches X 20 inches, Packed Uncompressed: 15 inches X 8 inches
Fill Weight: 1.5 lb., Pack Weight: 3.4 lb.
Dobby Diamond 250T Ripstop Shell, Softech II 210T Liner, YKK Zippers
Hibernate Extreme, Micro Denier, Continuous Filament Fiber Fill
T-8 Compression Sack, Synthetic Fill