That's not really true.
Some synguts are more elastic than some multis and some multis have less power than some synguts.
A good example is LightningXX(syngut w/power) vs. Mantis Comfort Synthetic(elastic multi w/very little power).
AFAIK there has been no testing for elasticity or loss thereof.
Neos 1000, Eagnas Combo 810