The differential cross-sections for elastic [sup 12]C-[sup 12]C scattering at 2400 and 1449 MeV are calculated on the basis of the multiple diffraction scattering theory and α-cluster model with dispersion. At the energy 2400 MeV the calculations were performed by means of "effective" and "free" α-α amplitudes. It is shown that the results obtained differ significantly.