How to use Data Shuttle to add rows without erasing changes made to target sheet?

I am using Data Shuttle to transfer a sheet of individual people activity from a source sheet to a target sheet.

I want to be able to add notes to the target sheet or check boxes in columns that are on the target sheet and not the source sheet. I set up DS to merge data into the target based on a key column value. Each time DS runs it erases all information on the target sheet and replaces it. I've tried this with different row options (add rows or add rows and update or just update) with no success.

Ideally, I would add new rows and update information on existing rows without removing comments, or data added to columns not on the source sheet.

Thanks, Sara