Add a Grand Total to the Sales Order Report when filter is set to ALL

Currently in the OE module, you can run an Open Sales Order Report, Closed, On Hold, and All. However, when the "ALL" report is selected it doesn't pull a grand total amount at the bottom like the others. It would save time reporting sales numbers if it had a grand total value rather than having to pull 2 or 3 reports per customer category per date range selected and having to manually add them to calculate all sales registered.