Looks as though you got the answer you were hoping to get. Powder stored well holds up nicely with age (within reasonable limits).

I have had a similar experience to that of RR and have had significant differences lot-to-lot sometime with Reloader powders. I still shoot quite a bit of Reloader but I try to buy a good supply of it with the same lot number to keep problems at a minimum. In the distant past some Win. powders chronographed a bit different but even they were not really bad.