Ratio of the statistical errors associated with the Kα- and L-shell-derived measurements, as a function of the ring temperatures, for the three clusters in our sample. The violet area represents σ_K/σ_L values (with their 1σ scatter) derived through high-S/B simulated spectra, as explained in the text. The errors are estimated following strategy 2 and through the joint fit of MOS and pn camera spectra of each region. For temperatures lower than ∼3.5 keV, the above ratio is higher than 1, meaning that the L-shell drives the abundance measurements.