Distribution of the Probability Integral Transforms (PIT) for each of the six models, and for the final PDFs. Each model exhibits a nearly flat PIT distribution, which assesses the very good quality of the PDFs. The PIT distribution of the final (averaged) PDFs (see Sect. 3.8) is slightly over dispersed, as expected from our pessimistic choice of combination. The dashed green and red lines result from expanding and shrinking, respectively, the Δz of a flat model by 20%.