In general, the analysis reported so far on short-time system+bath dynamics up to 300 fs has shown small differences between CT-TSH and TSH-ED, that even tend to disappear/reduce when increasing the number of degrees of freedom of the environment. Therefore, we find informative to investigate the dependence of the computational cost of the coupled-trajectory (CT-TSH) and of the independent-trajectory (TSH-ED) methods. We recall that all calculations are performed with the G-CTMQC code interfaced with QuantumModelLib , on a node comprising of two 16-core 2.30GHz Intel(R) Xeon(R) E5-2698 v3 CPUs with 192 GB of DDR4 2133 MHz ECC DRAM.