Testing the effect of masking on different methods to calculate average line ratios of mock-data. Same as Fig. A.2 but for line ratios between different mock datasets. The color gradient indicates the expected line ratio (measured via LR_true). The ratio of Mock41 and Mock227 results in the largest line ratio (and thus faintest data point). Two outliers with large ΔLR/LR_true are only shown as lower limits (colored triangle).