That's not a simple question but I reviewed a modern Vol 1 & 2 (uncollated) and my answer is that they tried to do it correctly including Back of Book. In most cases the regular issues from Volume 1 end cleanly so that regular issues from Vol 2 will collate correctly. I reviewed several larger countries and in most of them I think I could keep the various BoB pieces together except for Netherlands where the Dues and the Semis wouldn't work. I'm sure others have already figured this out.
I like the newer albums because of the heavier pages, I noticed the Colombia States were missing but I thought someone had taken them.
I do not regroup countries together from different Scott volumes because I like to think of each volume as the representation of world history in a given period. Because I stick to collecting till 1955 for now, I think of PART II to be the combined history of the world from 1941 - 1949, for example. This works for me because I still get to take advantages of the previous editions like reduced shelf space. When I like a country to collect separately (specialised) I will use self made album pages, and will have extras and duplicates for those countries anyways to fill spaces in the corresponding Scott volume.