Do they not teach you math, physics or engineering in the Navy... Some days I am so ashamed of my passport.
OK to the topic. You get a factor one fall at 40m when you fall 20m. This is because you have fallen half the length of the rope you have out. So lets simplify it and say you divided 20 by 40 and you got .5 Now, if you were to jump off a bridge with a 60m rope, you would also be falling the full 60m length... Causing a factor 2 fall, or 60 divided by 60 = 1
This is completely different as I hope this simplified example has shown. No the guys at petzl are pretty sharp at what they do...
Please don't bungee on your climbing rope... Amazing how much someone can learn from the names of the items they purchase... It is a CLIMBING rope, not a climbing/bungee rope.