  The constituent picture of hadrons implies certain quantum mechanical
inequalities which must hold in the potential models. Basing on this
qualitative consideration I argue that it is not easy to increase significantly
the scale of the flavor-dependent 1/m_b^3 effects within the heavy quark
expansion preserving the conventional constituent picture of heavy flavor
hadrons. I briefly address the physical consequences one might expect if the
effects of weak scattering and interference are attempted to be pushed above
the 10% level within 1/m_b expansion not invoking qualitatively different
mechanisms including violations of duality.
