Comparison between observed and calibrated stellar parameters for the 234 stars in the calibrator sample, based on the calibrations of M_V and subsequent derivation of radii, luminosities, and spectroscopic masses (see Sect. 4.5). Results are shown for both the SpC-based (upper row) and FW3414-based (lower row) calibrations of M_V. Each column corresponds, respectively, to the differences in M_V, radius, luminosity, and spectroscopic mass. Differences in radius and mass are expressed as fractional values relative to the observed quantities. The LC is color-coded as in previous figures; SB1 systems are marked with white-filled symbols. Dashed green lines indicate the ±1σ region derived from the scatter of the differences. Each panel also includes the mean offset and standard deviation of the residuals, providing an estimate of the typical uncertainty associated with each calibration.