In response to your pointing out why they would even have a red zone, i would surmise that, if anything, it is to let you know the tension is too high. But still, I've measured the tension with a
weight plate, and a mere 2.5 pounds puts you well into the red. But staying in the green zone might explain why some users, as I've seen in postings, have made no gains after months of dedicated usage. Maybe they were following directions and keeping it in the green. On the other hand, maybe the folks at PF are right, and keeping the tension higher ie red zone is counterproductive, and maybe the users who got no gains were doing that.
It's all very confusing! I assume that in the alleged PF clinical studies, all participants kept the tension in the green or yellow zones? Also, I should point out that in another of their emails, they recommended
NOT using any other method of enlargement. In other words, no manual stretching, no bundles, no [words=http://www.mattersofsize.com/forum/showthread.php?83577-Length-master-official-order-thread-now-shipping-06-16-2014!!!]
LM[/words], no [words=https://officialhydromaxpump.com/?uid=6&oid=2&affid=98 ]BM[/words], no clamping, no jelqing. Nothing!
I wonder if DLD or other experienced PE'ers on this site would concur.