[Ifeffit] sigma^2 values for multiple scattering paths

Hello, I briefly read through the FAQ about this but I'm not sure if it answers my question. Are there situations where the sigma^2 for a multiple scattering path can be smaller than the direct paths? So small that they're on the order of 0.001-0.003 for a degeneracy of 12 such paths? I'm working on a fitting model that does not work well with additional shells but it looks almost perfect with a multiple scattering path included. I'm skeptical however, because of the small sigma^2 values. I am also not discounting the fact that the data quality may be poor. But I would appreciate any physical reasons for small sigma^2 values. Thanks! han sen