Document Creation - Report Totals

I had to disable averages and totals from a report I use in document creation because it adds the additional row with no label, indicating it's an average or total. 

I saw a video somewhere showing how to add separate area for totals, but can't find it anywhere and it's not included in the Document Creation help. 

I'm creating customer invoices and the totals/subtotals are important. Hoping someone can point me in the right direction or provide the solution.