Overlaid posterior distributions from the primary POSEIDON retrieval and the independent SANSAR retrieval for a subset of shared free chemistry parameters. One- and two-dimensional marginalized posteriors are shown for the reference planetary radius R_p,ref, reference atmospheric temperature T_ref, cloud-top pressure P_cloud, and VMRs of H₂O, CH₄, CO₂, CO, and H₂S. Blue contours and histograms correspond to POSEIDON, while orange contours and histograms correspond to SANSAR. Values shown along the diagonal give the posterior medians and 1σ values. Both retrieval frameworks recover consistent H₂O, CO₂, and H₂S abundances, while showing modest offsets in R_p,ref and T_ref, reflecting differences in the forward-model implementations, prior choices, and retrieval assumptions. The cloud-top pressure posteriors are broad and not tightly constrained in either retrieval, with POSEIDON favoring lower pressures than SANSAR but both frameworks showing substantial uncertainty, consistent with the weak evidence for clouds.