In order to study how to reliably perform quantitative tritium and helium analyses in thin film samples using enhanced proton backscattering (EPBS), several EPBS spectra for some samples consisting of non-RBS light elements (i.e., T, 4He, 12C, 16O, natsi), medium and heavy elements have been measured and analyzed using analytical SIMNRA and Monte Carlo-based CORTEO codes. The non-RBS cross sections needed in the CORTEO code are taken from the ENDF/B-Ⅶ database and the calculations of SigmaCalc code and are incorporated into the CORTEO code. All non-RBS cross section data over the entire proton incident energy-scattering angle plane are obtained by interpolation. It is quantitatively observed that in EPBS analysis the multiple and plural scattering effects have little impact on the energy spectra for light elements and the RBS cross sections of light elements can be used in the SIMNRA code for dual scattering calculations. It is also observed that the results given by the CORTEO code are higher than the results of the SIMNRA code in the low energy part of EPBS spectra, and are in better agreement with the experimental data. Tritium and helium analyses in thin film samples using EPBS can be performed reliably when the multiple and plural scattering contributions are completely accounted.