Well, I reckon you "could" say the warning was for shot shell loaders, but considering "all of the "Dot" powders were designed for shotshell loaders, but are used by metallic cartridge loaders as well, it would be prudent for anyone loading powders to pay attention to any warnings on any of the shot shell powders when using them for metallic cartridges, since the same things that are warned about for shot shells would carry over to metallic cartridges, right?
You can see for yourself here about the "Dots", like Red , Blue Green, Clay, etc., if perhaps you were not aware. Note that at least one powder is used that is a metallic case powder, but is usable for shotguns as well, like Unique:
https://www.alliantpowder.com/products/shotshell.aspx
But only Promo has the warning about using Red Dot data, by weight, rather than volume for measuring. Thus, that is why I mentioned it as a reminder a while back in post #3. Because it is important to know, and the OP asked about info.
Glad to know you understand.
Apparently you have become good at it, & as well, apparently I didn't have to take the time to post what I did, but oh well... Life goes on & maybe it will help someone else someday.