As shown in Sec 3.2, the multi-level extension, especially for a target accuracy of NOR-MALPNO, relies on beneficial error compensation between the individual contributions DLPNO-CCSD and DLPNO-(T 0 ). However, for a target accuracy of TIGHTPNO, this error compensation is less pronounced due to larger errors for DLPNO-(T 0 ) compared to DLPNO-CCSD. Naturally, the orbital pair selection performs superiorily for DLPNO-CCSD. Hence, an improved description of the triples could have a positive impact on the error compensation.