Records will appear in Inspection Management for every delivery when you use a Receive Case on the Supplier for Purchase Part record that requires inspection either at the Arrival location or at a QA location. The frequency of records appearing here is not governed by a trigger on the Control Plan.
The trigger on the control plan determines when an Analysis is to be automatically created, e.g., every third receipt. You would then enter the inspection data in the analysis (variable and/or attribute and/or categorical).
So, for every receipt you will need to enter inspection results (approve, scrap, or return) in Inspection Management, unless you manually change the Qty to Inspect to zero or change the Receive Case prior to registering the arrival (I think you can do this), but you will not always need to complete an Analysis for every receipt.