It's not a company advertising the tires... it's a study of the tires themselves... not knowing what's in there, I'd say it's likely mixed brands and types.
Also, at a profile of 80, you have to consider that the deformation of the tire itself will play a very big part in increasing rolling resistance.
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As MetroMPG himself found out, an ultra-narrow, an ultra-light and narrow tire does not always make for less rolling resistance.
http://ecomodder.com/forum/showthrea...e92-19126.html
If all things were equal, that safety spare should perform better. In fact, the VW XL1 uses a very similar type of tire, at 115/80R15 (do note, sidewall height is exactly the same as on a 205/45 tire... so those are pretty low-profile sidewalls, anyway!). But they're not.