RV differences normalized by their uncertainties (added in quadrature) for stars with multiple measurements. The dashed black line represents the expected standard normal distribution for correctly estimated uncertainties. The observed distribution for 931 039 velocity pairs (purple line) is wider, with a fitted standard deviation of σ_in = 1.82, indicating underestimated RV uncertainties. After applying S/N-dependent scaling factors to calibrate the uncertainties, the resulting distribution (blue histogram) closely matches the expected normal distribution, with a fitted standard deviation of σ_corr = 1.05. These calibrated uncertainties were used for the RV variability analysis.