Keeping up with lots of the same powder do you pay any attention or just chime on? Maybe the manufacturer is great on control or your just that lucky? @ less than top pressure one would have better safety, but those who load at top levels might not be so safe? How often do you check?
Most of my loads are midrange, so I don't worry much about different powder lots. I also use commercial powders in about 98% of my loads, and generally speaking, commercial powders don't vary that much between lots. If you are using surplus/pulldown military powders, do be aware that different powder lots can vary considerably more than the commercial powders.