Effects of the non-toroidicity of the eigenmodes on the absolute difference between the real part of the eigenfrequencies for the compressible and Boussinesq models. The non-toroidicity Γ of the eigenmodes is calculated using Eq. (22) for the compressible model. The left column corresponds to uniform rotation, while the right corresponds to solar differential rotation. The different colours denote the different modes, similar to Fig. 5. Points of the same colour correspond to modes with different azimuthal orders m.