Ligament stretching should be unaffected by your starting penis length. However I can see how tunica stretching may be easier with a longer starting length. As you say a percentage gain for 8 inches is longer than the same for a shorter penis. Then again some would say your starting gitth at 5.5 could hold you back because it’s like a thicker rubber band being harder to stretch.
So I guess my answer is maybe. In any case I wouldn’t worry if I were you because you are already at many of our goal sizes already so even if you gained little you are still ahead.
What made you want to PE? I would imagine you’ve only had positive and probably “the biggest” comments so far.
OK, yea I have read before that bigger girth could decrease length gains but 5.5 inch girth is at the base so it’s not so thick. Sure there have been some positive comments but I would like to be a bit bigger and I wanna get an harder erection, sometimes it gets a bit soft during sex. And I’m a shower, not a grower, it’s over 6 inch flaccid sometimes almost 6.5 inch so it would be fun if it could grow more then 2 inch when getting hard.