You can group the results displayed in the grid by one, two, or three fields from the usage records.
The fields you can select in Summarize by These Fields vary, depending on what you select in the Bill Period and Unbillable Code fields.
If you select an Unbillable Code of All, the first "Summarize by" field is automatically populated with UnbillableCode, which you cannot change.
Note
To display any results, all three fields cannot contain None. An UnbillableCode must be selected in one of the three "Summarize by" fields OR be selected in the Unbillable Code field.