Error residuals δ_µ,i −δ_µ(μ, τ) (circles) as functions of cluster mass (left panel) and age (right panel). The size of the circles is proportional to the clusters’ contributions to the total surface density. Mean and median of the residuals (solid red and black lines, respectively) were computed using a sliding window of width 0.1 dex. Dotted lines in red and black denote the corresponding intervals enclosing one standard deviation and the 16th to 84th percentile, respectively. We note that a single outlying cluster with δ_µ > 2.5 lies beyond the y-axis range and is not shown.