We report x-ray photoelectron spectroscopy experimental results on band offsets at Ge/Si(100)2 x 1 interfaces grown by hydrogen and Sb-surfactant mediated epitaxy. For Ge deposited at 400 degrees C in Si(100)2 x 1, the valence band discontinuity was of 0.72 +/- 0.07 eV. Using atomic hydrogen and a Sb-monolayer mediated growth, we obtained values of 0.75 +/- 0.07 and 0.69 +/- 0.07 eV. Our data show that the surfactant Ge layer strain induced effects on the modification of band offsets are surprisingly negligible.