Shelf life depends on temperature. Ford Bulletin-
https://www.fcsdchemicalsandlubrican...%20Quality.pdf
There have been several reports of tampering, containers have been opened, used and refilled with water then returned for refund. Look for tampering, be sure seal is intact. White powder around cap may indicate it been opened.
Mercedes Sprinter has no regen indication. Occasionally I get a "hot medal" smell while driving. Most of my driving is at highway speed.