Change the default time a scheduled task can run from 72 hours to

Is there a command line to use with schtasks.exe to change the default time
a scheduled task can run from 72 hours to 1 hour? If not - is there another
automatic method for creating a task and setting this option?

Where is the registry key located to modify this 'DEFAULT' value from 72 to
1 or whatever?

remember that this is 'NOT' the AT registry of 'atmaxhours' they are not
related and does not work for scheduled tasks.

Thanks to all