Results of simulations for low-mass ETGs (σ = 150 km s⁻¹; see the text), showing the ability to recover individual abundance ratios as a function of S/N ratio, using different techniques, i.e., full spectral fitting (black), full-index fitting (red), and index fitting (blue), as labeled in the top–left panel. In each panel, solid lines with filled circles represent the 1–sigma uncertainties on abundance ratios, while dashed lines show the average difference between recovered and input values. Each panel corresponds to a different element, arranged in the same order as in Fig. 3.