Glad you asked, @Sjc200! These Motion Schedule options are only for camera enabled products (Doorbells/ Cameras). While there is not a scheduling option for the Alarm Motion Detectors, there is a Modes feature that allows 3 different Modes to be customized to include or exclude devices depending on scenarios home, away, and disarmed. This feature can be used with your Camera enabled devices and your Alarm devices.
There is also a quick way to control your Alarm Motion Detector notifications by visiting the Menu, selecting Settings, and then selecting Alarm Alerts. While it is not scheduling, it is still a quick way to enable/ disable alerts when wanted. I hope this helps!