Comparison of rotational splitting asymmetries Δω_asym computed from the NDE, generalised DG92 and π-γ formalisms. Results for the π-γ formalism and the generalised DG92 formalism are shown in the left and right panel, respectively. Here, the evolved model was used to compute the synthetic data. The shaded band indicates two times the minimum uncertainty of the averaged splittings obtained from Eq. (15). The multiplication by two is necessary because Δω_asym is twice the frequency difference between the averaged and actual rotational splittings. As a minimum uncertainty of the observed frequencies we assume the frequency resolution. Then the minimum uncertainty of the averaged splittings is computed from error propagation as ${\sigma }_{\delta \omega ,\min }/(2\pi )=1/\sqrt{2}\delta {\nu }_{\mathrm{res}}=1/\sqrt{2}\times 0.0078\mu$Hz, given the four years of Kepler observations.