The APLs evolution in Fig. shows how areas converge towards the target experimental APLs. These curves are, in most cases, highly correlated to the loss evolution curves due to the square difference penalty in the loss function shown in Equation . For some systems (DOPC, POPC, DOPG, POPG, DMPG, DOPE, DMPE) we obtain very good agreements with the experimental values, while in other cases (DMPC, DPPC, DPPG, POPE) the APL curves seem to diverge. Generally, the mean absolute error is 0.02 nm 2 , corresponding to an average 3.8 % deviation from the experimental reference. In the worst case (POPE), the absolute error is around 0.04 nm 2 , (≈7 % deviation). It should be noted that these differences are within the variability found for different experiments performed with the same lipid at similar conditions. The average APL deviation is also just slightly larger than the values obtained in a recent refinement of the MARTINI 3 force field, which are up to 4 % in their worst cases. Even though the study of Empereur-mot et al. also targeted the APL as one of the observables, the authors used different mappings and focused on optimizing the intramolecular bonded terms, which were not the focus of our optimization.