You can also add new Rollup date fields in Spreadsheets and reports. It indicates that a top-level object’s dates are based on the dates of items within it. When you roll up dates, the parent task or object’s dates change and are rolled up from the items within it.
In the Column Filters tab, you can add the following rollup dates:
Rollup Schedule Start Date
Rollup Schedule Finish Date
Rollup Task Schedule Start Date
Rollup Task Schedule End Date
For Rollup Task Schedule Start Date, Rollup Task Schedule End Date fields, a Task type lookup is added in the Column Filters tab.