Open the list of expected additions, click the checkbox to the left of the line and choose Edit or Delete in the menu.
How to do it
Open the production code and select the Expected Addition tab to see the list. Don't click Add.
Click the checkbox to the left of the line, and a menu opens.
Choose Edit to change it, or Delete to delete the entry.
Change the amount in the dialog and click Confirm.
Good to know
Look for duplicates, for example several lines with the same amount.
When you sign the contract an expected addition relates to, you should delete it or enter it in the contract. Otherwise the cost is counted twice.
If you want to preserve the history, you can instead add a new entry with the opposite sign.