Here is an explanation of both types of rules:
Department Rules – If the grace periods and length of breaks/meals are dictated by the department.
Shift Rules – If the grace periods and length of breaks/meals are dictated by the shift length.
One question that may help you decide which is best to use for your company:
Is there ever a time that the meal break length changes based on how long they work?
ex. 5 hours they get a 30 minute break and 8 hours, they get a 60 minute break?
If you answer YES to the above question, you should select SHIFT RULES.
If you answer NO to the above question, meal length is always the same, you should select DEPARTMENT RULES.