Two ways:
From the team-member costs page (fastest):
1. Go to Finance → Team members.
2. Click Edit deductions at the top. All assignments get an input field for the deduction in euros.
3. Adjust the deduction amounts per assignment and save.
4. Click Done editing to return to view mode.
From the client profile:
1. Open the client → tab Team.
2. Click the specific assignment (Setter / Closer / Sales Manager) → Edit.
3. Enter the deduction and save.
The change applies immediately from the current month.