In this work, the independent scattering model is re-constructed using a new method which precisely aligns with the physical mechanism of the attenuation caused by multiple scatterings. Using the multiple scattering theory-based collocation method, extensive numerical simulations are then conducted for nine different fiber-reinforced composite materials. By comparing between the numerical simulation results, the performance of the independent scattering model is highly related to the type of the corresponding single scattering, which has been divided into three categories specified by the directional far-field scattering magnitude patterns in this work. The results show that independent scattering model works well for cases with backward-dominated scattering and overestimates the attenuation for cases with absolute forward-dominated scattering. The independent scattering model also apparently performs better for low concentration problems than high concentration problems regardless of whether the single scattering is the backward-dominated scattering or the absolute forward-dominated scattering.