Additionally to the round-trip accuracy, which rewards models that propose a large variety of reactions given the target product, one can calculate the round-trip coverage . In short, the round-trip coverage holds a weaker condition than the round-trip accuracy: Only 1 precursor set out of k needs to be "cycle-consistent". This is to ensure that models can generalise on a variety of different molecules. In the investigation, it was scrutinised that most frameworks perform equally well on this metric. Thus, the analysis of the round-trip coverage can be found within the supplementary information (Section S2).