If the minute isn't specified when creating an Advanced Time Interval trigger, the task seems to run repeatedly for an hour. IMO, it should run once at the top of the hour instead of having to specify the "00" minute. This would be even less of a deal if one could edit triggers.
The other "issue" is more of a typo/grammar thing. If I am interpreting the name of the "Restart the Minecraft server if it empty" task then is should probably be named something like "Restart the Minecraft server if it is empty" or "Restart the Minecraft server if no users are logged on"