We compare experimental triply differential cross sections for single ionization of He for small (100 MeV/amu
projectiles) and large perturbation (3.6 MeV/amu
projectiles). For electrons emitted into the scattering plane at the small perturbation, the data are well described by our calculations. For the large perturbation as well as outside the scattering plane for the small perturbation, in contrast, serious discrepancies especially with the continuum distorted wave-eikonal initial state (CDW-EIS) model are found.