Difference between the means of the VLC and re-computed LC time series for all our stars ordered by spectral type. For RV constant stars (black filled circles) there occurs a systematic offset of 10.4 ± 7.7 m/s (red solid line and red dashed lines). Stars shown with open circles were not included in the offset analysis (for reasons see comments in Table 3). The shown error bars correspond to the uncertainty in the means, i.e. parameter s from Eq. (1).