Smelling a fragrance directly from its package gives you a concentrated impression. Once that same fragrance is dispersed throughout a room, its individual notes can become easier to separate and the overall balance may feel different.
Temperature, airflow, room size, nearby odors, and even the materials in your home can influence what you notice. Your nose also adapts as you spend time around a scent. This is one reason it is worth experiencing a wax melt or home fragrance in the space where you plan to use it instead of judging it only from a quick sniff of the package.