I have come across some H380 that is much, much slower than it should be given its position on the charts. I have also found widely varying load data for it from different sources.
My experience exactly. I've been reloading since 1968, and H380 has shown me the widest lot-to-lot variation of any powder I've tried. I used to shoot a lot of it in the .22-250, and even a bit in the .30-06/150 gr, but every time I bought a new batch, I had to start all over with load development.
Now, I haven't bought any H380 in prob 15 years now.....it may be more consistent now. As for H335, I use tons of it in .223, but none in .30-06.