Figure depicts the ground state energy curve of xBW2 as a function of U/t. Here, we compare xBW2 to MP2, Variational Coupled Cluster with Double excitations (VCCD) and the exact full Configuration Interaction (FCI) method. VCCD is included here as it represents the best possible energy that can rigorously be obtained with an MP2-like wavefunction. Indeed, VCCD only slightly underestimates the correlation energy in the strongly correlated limit, while MP2 diverges. As with the HEG, this is despite the fact that the energy gap retains its finite value for all correlation strengths. Interestingly, xBW2 displays a massive improvement over MP2, essentially curing the strongly divergent behaviour of the latter. The xBW2 curve in fact displays excellent quantitative agreement with the reference methods, somewhat fortuitously falling between the VCCD and FCI curves.