In this study we show that ML models fit to Crippen logP values do lead to heatmaps that are in slightly better agreement with the ground truth heatmap derived from the atomic contributions of the Crippen model. However, when using finger prints (FPs) as the molecular representations there is a fundamental limit to the correlation that can be obtained due to the fact that the FPs are inherently fragment based and not atom based. We show that when the ground truth heatmaps are adapted to reflect this fragment-based nature the correlation is increased significantly.