I discovered this paper size change late last year when I was making test prints on a few papers from different manufacturers. I'd done the best I could on one paper and was then seeing what I could get out of the neg on another. I was squeegeing the prints on a perspex board and lining them up next to each other. I soon found that one of the earlier tests which had air dried for an hour or so was considerably shorter than the newer, still damp print. Quite a surprise. I'd forgotten about it until now, so it's good to get an explanation.