Hello bodhi,
I think that was the reason why I wrote my own script.
I had also wondered why I didn't just use “rtcwake”.
However, I've been using the script for 7-8 years and can't remember the details.
I have attached my script so you can test it by yourself.
At the top of the script you set the day and time for the next start.
The script calculates the next start time in seconds and set it via echo into “/sys/class/rtc/rtc0/wakealarm”.
After executing the script, I shut down the NAS with the “halt” command.
Thats all.
I hope that helps
Otto