We show that the approximations used to extract the damage depth profiles from the RBS-channeling spectra of high energy ion implanted lithium niobate lead to incorrect results when two defective regions containing damage generated by electronic and nuclear energy deposition are produced. We demonstrate by high resolution X-ray diffraction analysis that the end-of-range defects formation is not influenced by the onset of different defects in the surface region and it is thus independent of the implantation energy. We propose universal curves, valid for ions Z