I don’t know if the customer service knew anything scientific about penis growth. By what I know, vendors of commercial devices don’t know anything deep about this subject: they only think :”Keep it pulled, and it will be longer.”
So said, connective tissue elongation tends to plateau after a given number of hours/day under tension. The penis is mainly composed by connective tissue. Make you the sillogism.
I think this is totally true. Really, I don’t think you can count on info you get from a vendor. You have to go to the forums and to sites that don’t sell, but are up as info databases. Here’s one I read often, and they have specific info on extenders: