Use the Add Mode and Default Quantity fields only for auto-add or auto-replace product relationships.

The fields "Add Mode" and "Default Quantity" in Salesforce Industries CPQ are specifically designed to be used for auto-add or auto-replace product relationships. These fields dictate how products are automatically added or replaced in the CPQ configuration, such as adding a mandatory accessory when a main product is selected or replacing an existing product with a new version, ensuring that product configurations remain valid and complete.