Compact remnants left behind the Z_⊙ single star SN progenitor models S21 and H16, predicted by the M16 SN model, are compared with the trends of progenitor ξ_2.5 with M_CO. The ξ_2.5–peaks are shifted towards higher M_CO in S21 compared to H16. The peaks are at ≃4.8 M_⊙ in H16 but at ≃7 M_⊙ in S21, and at ≃9 M_⊙ in H16 but at ≃13 M_⊙ in S21. For improved visual discrimination, the sparsely sampled S21 models are connected by lines (in blue).