Dave, you can't really compare loading data from Norma charts, with loadings from any US manual, or loading guide, in that the old Norma charts were as dead on as could be, while all others are usually exaggerated. So I did some digging and found some interesting figures from early Norma guides and charts.
Norma 203 is by far their most common powder, used in the greatest number of calibres. I used it in the 30-06, 55 grains for 150 grain bullet and 50 grains for 180, with a shown 2700 fps. We had no means of actually testing velocity, but years later when I had access to an Oehler, I still had some of the old original 203 I had once used, so I loaded 50 grains with a 180 Norma bullet and the Oehler read 2690! And this was with a 30-06 of mine that turned out to always read low, as compared to my 30-06 rifles.
Now it gets interesting. An old Norma guide I have gives loadings and velocities for Norma powders, as well as US powders. Here is what I found with the 243.
A 75 grain bullet and 42.1 of N203 (old) gave 3,500 fps. for the 243.
Looking in the section on US powders, they show 42.3 of 4064, for 3,500 fps.
In the old Norma guide, 7x57 and 150 grain bullet, N203 powder, 42.1grain for 2756 fps.
" " " " " " " 4064 powder, 42.3 grains for 2756 fps!
In other words, the old N203 and 4064 can be deemed to be equal.
A couple of years ago I did considerable load checking for two family member rifles in 7-08, hence to my notes.
Using a Savage and a Tikka rifle, 7-08 and 139 grain bullet, 42 grains of 4064 and 42 grains of Re15, got identical results, considering the variances of two rifles and normal chronograph variances.
Short answer, The old Norma 203 seems to be the same powder as Re15 and 4064.
Bruce