Yeah, the 4.0 was a long time ago. I still need to change that. But it doesn't go above a 6 for me. Maybe others find it different. My wife mentioned that once. I just don't feel it anymore myself.
4.0 for longevity? It lasts a solid 8 hours on me with good sillage. It's a scent I really enjoy wearing and it gets me quite a few compliments. It performs best around 18-23 degrees.