Inspection lot created date, start date, end date and GR processing time.

Can someone please explain how the created, start, and end dates are generated for inspection lots in QA32. I am trained on the QM side, but have little experience with PO's or other upstream processes.

Our lots are both created by manufacturing (04 inspection type) and purchased materials (01 inspection type). I can see no correlation between the created date or start date and the SAP calculated end date. We were told that the GR processing time is the key, but am having troubles finding the details.

Thanks,

Chris