It makes sense to me! Normalize it to the typical humidity that it will be stored and loaded at then you will get not only consistent burn rates but also more consistent powder charges as the powder won't lose water weight as it ages.
I have been normalizing all building materials on remodeling for a week minimum prior to installation for the last 2 years. Cracking, sagging, and misalignment repairs after doing the finish work has dropped to almost 0. Normalizing materials makes for a better finished product. I don't see why it wouldn't work for reloading.
Jay
