Difference between astrophysical_parameters.age_flame with the age derived using the SPinS code normalised by their joint uncertainties. The Gaussian represents the ideal case but centred on the peak difference (−0.4σ) of the results using all stars irrespective of their evolutionary status. The input data are identical, and we assumed a solar-metallicity prior for both codes. We highlight the sample of MS stars discussed in Sect. 3.3.2.