As I read the scrip given in the link there is no way to use the scheduled recording time to automatically deduce the next wakeup time. Or should a take a break or coffee?
However, could you explainwhat part of the software creates "/var/cache/vdr/acpiwakeup.time". Is it automatic as soon as you have scheduled recordings?It is written by the script S90.acpiwakeup that is called from the vdr on shutdown.