νF_ν SEDs of Jin et al. (2012) and Pezzulli et al. (2017) families, normalized at 13.6 eV. The normalization energy is marked by the vertical dashed line; amplitudes are in arbitrary units and are used solely to compare spectral shapes. The Pezzulli et al. (2017) SED is harder near the hydrogen-ionization edge, leading to stronger excitation of high-ionization lines such as He II, whereas the Jin et al. (2012) SED exhibits a more prominent soft X-ray tail, contributing extra ionizing photons above the He II edge (54.4 eV).