1. SAP S/4HANA Help Portal
Quality Management (QM)
"Update of the Quality Level": "The system updates the quality level at the following two events:
When an inspection lot is created
When the usage decision is made for an inspection lot"
(This source directly confirms that both creating an inspection lot and making a usage decision are the triggers for updating the quality level.)
2. SAP S/4HANA Help Portal
Quality Management (QM)
"Dynamic Modification Rule": "The system determines the inspection stage for the new inspection lot on the basis of the quality level. [...] When the usage decision for the inspection lot is made
the system updates the quality level on the basis of the rules defined for the stage change."
(This documentation clarifies the role of both events: lot creation uses the quality level
and the usage decision updates it.)