Comparison of RMSE on the observational space for small dX and large dX groups for different $T_{\text{eff}}^{\text{TF}}$ ranges. We use both the Clean and Uncertain groups in this figure. K- or G-type samples are divided into late K types (up to K6 type) and early K and late G types (K4–G9 types). G8-type stars are excluded in this figure. The first and the last columns present the difference between the RMSEs (goodness-of-fit) obtained by the two different methods and the second and third columns show the number of samples where the corresponding method has a better fit to the original input spectrum. Purple bars are the cases where RMSEs of the two methods are similar to within 0.3 × 10⁻⁵.