In the present paper a modified semi-analytical approximate method for determination of polarizability and ultimately optical properties of cuboid nanoparticles for different incident polarizations is suggested. Except sphere, in other particles depolarization factor strongly continents on the position of the point inside the particle. Each point represents an electric point-dipole, approximately defining the optical response of the nanoparticle in quasistatic regime. Using the near field distribution inside a cuboid nanoparticle the proper off-center point as representative of the whole shape is determined. Actually in this point electric field has a mean value and depolarization factors of it could predict the optical properties of nanoparticles properly. For perpendicular polarization because of the weak dependency of the electric polarizability to the considered dimensions, center point polarizability is still a good candidate for determination of the optical properties. However, as the height of cuboid increases the deserving point moves toward the top/down surface for parallel polarization. Interestingly, assigned the point-dipole at this off-center point can predict the optical properties of the considered plasmonic nanocuboid with a good approximation. This point-dependent (PD) MLWA technique could be generalized to different nanoparticles with an irregular shape.