Let us call t FS = t high the average CPU time per step spent in a standard FS-TSH simulation with a "high" level functional. This time takes into account the SCF optimization, the solution of the TDDFT equations as well as the calculation of the FS probabilities. In the following we use t FS as a reference CPU time. In order to provide fair comparisons, we also need to consider the average CPU time per step from a LZ-TSH simulation with a "low" level functional t LZ = t low .