We are now interested in exploring whether the different extrapolations of List 1 for consecutive X=D,T,Q,5 cardinal numbers improve or deteriorate the GTO CBS estimates as compared to PW energies. When uncorrected for the BSSE, HF and MP2 interaction energies converge non-systematically and sometimes non-monotonically because of the varying balance between BSSE and BSIE (as illustrated in Fig. or Ref. 15). For this reason, GTO extrapolations performed on relative energies yield results that are either very similar or worse than those for absolute total energies. Thus, in what follows, the energy of each subsystem will rather be extrapolated individually.