Slanker: Jelqing doesn't lead to peyronie's disease. PD is caused by plague build up in the tunica within the penis. Jelqing can, however, cause a curved penis if you don't use proper technique. Make sure you are putting the same amount of pressure on both sides of your penis, and that you aren't focusing on one side more than the other. Same goes for stretching - make sure you stretch in all directions, not just one.
For the urologist that said jelqing doesn't work: Tell that to the
900+ men that took my PE survey. But similar to exercising at the gym, it can be dangerous if you go overboard. Since you have morning and night wood, you most likely don't have a problem. Heck, you're probably going to need to actually increase the intensity at this point (since you're not gaining and you have
positive PI's).