For anyone that has run across this date coding - 20192423003 - on a box of Peak Blue DEF:
I call OWL (licenser of PEAK Blue Def manufacturing) this morning. In the above number the 2019 is the plant code. The 24 is year plus one, so 2023. The 230 is the days PAST in the year before made, so Aug. 18, 2023.
This is different than the codes that start with letters, like GA24230xxxxx. Here GA is the plant code, 24 is year plus one, so 2023, and the 230 is the days LEFT in the year after made, so May 15, 2023.
These are different yet from the codes in Post #9. I asked the guy why they can't use the same coding. He replied that each licensed manufacturer uses their own date coding.
I guess this means that when you see a different code, PEAK didn't change it. You just got a box from a different production plant.
He also gave me a good understanding of the benefit of using the Blue DEF platinum. He said it resisted the formation of crystals and can help clean up existing crystals (help, not cure). He explained that for steady use, you probably don't need it. However, for less frequent refills, like an RV tow vehicle in the off-season, it might be worthwhile.
He also emphasized to examine the box and lid carefully for tampering and to make sure the funnel packet was sealed. Also, do not use a different funnel unless there is no trace of oil or fuel on it, i.e. perfectly clean.