Indeed, MP2-MBE(n) fluctuations for F -(H 2 O) 15 clusters are larger than those observed for HF-MBE(n) calculations. Finally, we comment on how denser quadrature grids impacts computational cost. The cost to evaluate the exchange-correlation quadrature is proportional to the number of grid points and ultimately O(N ) with molecular size, although it can be a significant fraction of the computational time for semilocal functionals. The cost of SCAN-MBE(4) calculations on F -(H 2 O) 15 is listed in Table for various quadrature grids. The SG-2 grid is deficient for such calculations but is included as a baseline, since this is a typical grid used for meta-GGAs in conventional quantum chemistry. SG-3 is satisfactory for MBE(n) calculations, and its cost is functionally equivalent to that of EML(75,302), and both exhibit similar errors. Further testing is required to fully differentiate the performance of these grids for DFT-MBE(n) applications, but the present work serves as a cautionary note that supramolecular tests may not reveal problems en- gendered by MBE(n) calculations. This is analogous to the manner in which MBE(n) is more sensitive to numerical thresholds as compared to supersystem calculations at the same level of theory. In summary, while meta-GGA functionals have distinct advantages compared to functionals situated at lower rungs on Jacob's ladder, their more stringent quadrature grid requirements are significantly amplified when such functionals are used in conjunction with the MBE. In particular, the SG-2 grid (which is otherwise recommended for meta-GGA functionals such as SCAN and ωB97X-V), results in cumulative errors that can mask other artifacts, including SIE. To eliminate the grid errors, we recommend the SG-3 grid or (in case of doubt) an unpruned grid such as EML(75,302). This does not eliminate SIE-driven delocalization errors, and MBE(n) calculations with meta-GGA functionals remain divergent even if the order-by-order fluctuations are greatly reduced through the use of high-quality integration grids. However, by saturating the grid and removing it as a source of error, other strategies for mitigating SIE can help, which were unsuccessful in calculations based on SG-2. These include the use of hybrid functionals such as SCAN0, low-dielectric boundary conditions (based on a PCM with ε = 4), and DC-DFT (DFT@HF), based on a self-consistent HF density.