static elongation vs dynamic

I was hoping there might be an engineer with some rope knowledge out there that might know the answer to this one.

I was curious about the difference between a couple half rope ratings, specifically the PMI fusion 8.6 and mammut genesis 8.5.
Genesis has an impact force of 6kn versus the fusion at 5.5kn.
Genesis has a static elongation of 9% versus the fusion at 6.4%.

I was told by a PMI rep that the rope uses the same sheath as the beal cobra (sister companies) but a slightly more static core. While the climber is decelerating I'm sure the static elongation would be used up rather quickly while most of the deceleration would be past that (in a hard fall), if that is the case clearly the PMI is the better rope to give a softer fall and less static stretch.
How could they achieve this technically? I thought rope manufacturers have very similar processes these days...

ps. on a side note, anyone have any trouble with the PMI fusion pigtailing and kinking?

Dynamic elongation is the stretch measured together with the impact force; that is, in one of those harsh standardized falls. For the Genesis it's 31%, while for the Fusion it's 30%. The Fusion still has slightly better specs, but not as much as the difference in static elongation would indicate.

While the raw material is often the same for different rope manufacturers, the treatments that it is subjected to are somewhat different and account for different specs. I seem to recall that Mammut, Sterling, and maybe others have literature on their web sites describing the kind of process that makes a rope out of nylon strands.

Also take into account that the force in an ideal spring is proportional to the stretch, but in a real rope, it varies non-linearly with the stretch and also increases with the speed at which the rope is stretched. A rope stretches less in a fall than during a slow pull test with the same maximum tension.