Three distinct colors encode the three DIBs λ5780, λ5797, and λ6614 for the HQ samples with over two epochs. The panels in the first column present the distribution of the number of epochs. The panels in the second column depict the cumulative distribution of the standard deviation of the EWs (σ_EW). The panels in the third column display the cumulative distribution of the coefficient of variation (σ_EW/EW_mean). The panels in the fourth column show the scatter of the σ_EW/EW_mean as a function of the EW_mean.