The rotationally inelastic cross sections, integral and differential, are computed as quantum processes using a published interaction potential and are compared with recently available experimental data at low collision energies. Different coupling approximations are analysed and the mainly repulsive interaction potential is confronted with the one exhibited by the system. It is found that a full coupling of angular momenta is needed for accurate comparisons and that the long-range anisotropy of the employed intraction is still not adequate to quantitatively reproduce the experimental data.