I saw Cyborg4Life's interview with Dr. Paley, he's strict with what increases he allows and claims to always prioritize health and ability to return to normal over height gain. He says that he makes it his goal to make sure the patient can return 100% to the mobility and athleticism they had pre-LL and he seemed confident of that claim, so I assume that if everything goes right you should be able to get to at least 90% normal minimum. So no it's not true. The only catch is that it can take you a long time to return fully back to normal, potentially 2 years in some cases.