I have the new one and some left from my old bottle ,and the fresh stuff lasts extremely well on me.
If MI lasts good on you, you should not have problems with this one. 4 till 6 hrs comes close enough.
By the way, you say a longevity from 3 till 4 hrs is below average? I think thats good to me. With new fragrances these days I'm happy if I get a longevity from 2 hrs.
If you have dry skin,..hmm I dunno. Maybe you can ask Bergdorf to send a sample from the new stuff first?
The old bottle one doesn't last longer anyway, but I suppose this bottle is about ten years old. I'll keep the bottle for memory sake.