My guess and it's only a guess, is the plastic in-between the glass layers is thicker on the new stuff for safety and weight savings. I used to cut glass for locomotives and other railroad equipment back in the '80s. It wasn't an exact science, it was all done by hand. We used to cut the glass on bo th sides as closely aligned as possible. Then bend it enough to snap it and then cut the plastic with a razor blade knife. If you bent it too much it would chip the edges of the glass. Then we figured out a new way to do it by putting lighter fluid on the crack and lighting it up to melt the plastic. A lot less chipped edges that way. Anyway, I wished the plastic in the glass was thicker back then. It would have been easier to work with. Lol
