This is already implemented. In the Transactions tab, type the address you're interested in (or it's label) into the search bar, then click Export. Open the resulting file in your spreadsheet software. You now have a list of all transactions associated with that specific address in spreadsheet form, ready for you to calculate totals, copy part or all of it into another spreadsheet, or whatever else you want to do with it.
Didn't realize that. That does make it a bit easier.