Weighted mean rms scatter around the best fits (top) and mean formal RV uncertainties (bottom) for HARPS, HIRES and CARMENES. The CARMENES data are more precise and have a lower scatter when compared to HIRES. The internal errors of HARPS are usually smaller than CARMENES, but comparable in terms of RV scatter. The rms scatter for GJ 15 A and GJ 1148 is averaged from the orbital solutions for these two targets given in Tables 7 and 4, respectively.