What Does It Mean by Using Existing Rules for a Cost Category?

Using existing rules for a cost category lets you flexibly define a rule that dynamically inherits the value of a cost category or enterprise project to group your costs.

For instance, you can use a tag key, Group, to tag your resources with values as team1, team2, and team3. After you create a cost category, with an inherited rule, the cost category will automatically group your costs by team1, team2, and team3.