What is the difference between Active Amount and Benchmark Amount on Expense Location Amt page

What is the difference between Active Amount and Benchmark Amount on Expense Location Amt page.

On the Employee Update Profile > Organizational Data page the field "Per Diem Amount Type" has options Active Amounts and Government amounts.  Is the Active Amount here represent the Active Amount on the Expense Location Amount page; and Government amount represents the Benchmark Amount on the Expense Location Amount page?

Does the "Exception Comment" appears when an expense type (Breakfast) exceed the GSA/Expense Location Amount value?

Does "Exception Comment" appears only on Travel Authorization or both Expense Report and Travel Authorization?

What setup/configuration/check box(s) needs to be implemented/turned on in order for the