Just to add a new perspective on this:
You can create inspection lots with the origin 15 as often as you like as long as your master data is in place (inspection type active, inspection plan, etc).
If you don't want to involve the ABAPers, build a query joining QPRS and MCH1 (join on MATNR, CHARG) or MCHA (join on MATNR, WERKS, CHARG), and use that to direct your use of QPR5.
Then periodically run QPR5 report to view physical samples with their respective store until and SLED entries. From there, create and process your inspection lots.
This is a manual process, but it brings your annual reserve sample inspection into SAP without any custom development.
If you want to go down the path of custom development, use the store until date as the date for your annual sample, and append a new field to QPRS table that will copy the current SLED for that batch from MCH1/MCHA table? Then use QPR5 as needed to create inspection lots.