Larry;
Hmm, does seem to be some inconsistences here in the designations. I don't have copies of those books, but understand I am in no way doubting your word on this. Everything however I can come up with which gives a DE vs velocity gives the 3-1 load at a nominal 1255 with a 1290 vel for the 3¼-1 load. This had seemingly been very consistent over the last 50+ years with the exceptions you mention.
My personal favorite for a 12ga 1oz load is to not exceed 1200fps which can be loaded to both a pressure level consistent to older doubles & a mild recoil in even light wt guns. My first experience with loading shells of this level came many years ago when I purchased a lot of the then new Hy-Score powder (pre 700X) & loaded 1oz loads to a nominal 1150fps @ about 8K psi. I fired a large number of these loads afield through a pre 1900 J P Clabrough damascus, which I shot extremely well.
I had no qualms then,nor do I now, about using loads with a relatively quick powder @ pressures up to 8K in a damascus gun with good condition bbls having a good wall thickness in the chamber area.


Miller/TN
I Didn't Say Everything I Said, Yogi Berra