Adding Grouped column returns greater sum total of all results

I have a case with NS Support, and they insist the behavior is correct. My most recent response to them is this: To be clear then, you believe that adding a column to include a Grouping of the transaction numbers actually pulls in additional transactions? The “Group” notion is purely a roll up of search results. Remember, we’re referring to the Totals of the results (the ones that add up the amounts across all the line items and displays at the bottom of the page).

We built a saved vendor search with the following setup:

Criteria:
- Inactive is false