You can customize a service code fee at the client level. Here's how:
1. Navigate to the Client you want to edit.
2. Click on View/edit client info.
3. Click on the Billing and Insuance tab.
4. Scroll to the section that says Client's Default Service. Select a code from the dropdown.
5. Edit the service code fee by clicking on the box with the dollar amount.
6. Click on Save.
From then on, every time you create a session for this client with that service code it will include that fee.
Note: Keep in mind that updating the fee here doesn't update any past sessions or invoices.