When clicking in to a row in your table, a couple of options appear to the right and left of your row:
Each of these allow you to add to, remove from, or change your table to suit exactly what you need.
To add a row, click on the + button that appears to the right-hand side of your row:
This will add a row directly underneath your proposal.
Need that row somewhere else? Click and drag the slider box on the left-hand side of that row either up or down to move it in the table:
To delete a row from your fee table, click the trash can icon that appears to the right of the row: