What I noticed in each of the power supplies: They went * never * broken during operation, but simply worked at some point no longer, if they had been separated in the meantime from the mains and then again wanted to put it into operation. Quasi disposable devices: Once switch it on and simply disconnect from the mains never again.
Conclusion: to assign a rating for this is actually still too much. But less is by design not possible. Another replacement power supply does not come into my house, I am now looking for a network hard drive from another vendor.