The numerical quality of the implementation is assessed by measuring the fluctuation of the total energy through QM/MM-MD simulations of the solute-solvent systems in the NVE ensemble. Both BO and CP approaches are investigated either using a full short-range coupling for the entire system or including also the long-range coupling with short-range cutoffs of 28, 30, and 32 a.u. for Wat(aq), Ace(aq), and BuOH(ace), respectively. The results are presented in Figure where the fluctuations of the total energy per particle over time is shown relative to the average energy. In all cases, the energy profile displays fluctuations with negligible drift, showing that stable simulations can be performed using the MiMiC-based QM/MM implementation. In the case of Wat(aq) and Ace(aq), the energy fluctuations are larger and more irregular compared to BuOH(ace). This is most likely related to the difference in the size of the systems combined with the use of non-periodic electrostatic QM-MM interactions.