Our MFCC-MBE(2) method consistently handles fragment-fragment, fragment-cap and cap-cap interactions without double counting. In addition, it includes the 1-3 fragmentfragment interactions that are commonly neglected. We found that using a simplified MFCC scheme with hydrogen caps instead of ACE-NME caps can avoid complications with fragment-cap and cap-cap interactions, but introduces large errors and is thus not useful for practical applications.