When you compare the PerfumeWorld classifications, the H&R classifications, the OsMoz ones and the Michael Edwards ones, you will see plenty of examples where they don't agree. Clearly, the individual classifier used some discretion in coming to his or her conclusion.
Hugo Dark Blue Â*- an ambery fougere by H&R, an oriental spicy by PW and OsMoz, and a mossy one by Edwards (I go along with Edwards)
Egoiste - an oriental spicy by H&R, an oriental fougere by OsMoz, a woody spicy by PW (I can't see what's oriental about it)
Tiffany for men Â*- Oriental Ambery by H&R, Woody Chypre by OsMoz, and Chypre Floral by PW Â*
All scents can be classified, but plenty of experts don't classify an individual scent the same way. If you think about a scent and sniff it Â*a lot, you can usually identify some element that led to their decisions, though it wouldn't necessarily have been the dominant factor were you making the decision.
Also, the classifications don't always match up among individual classifiers. For example, the H&R charts use the term Aldehydic in classifying female scents. But they don't use it in classifying Â*male scents. So aldehydic male scents like Perry Ellis 360Âº get lumped into chypres, which is inconsistent with its classification had it been a female scent.