It's important that the fragrance binds and mixes in completely with the melted wax. For this reason, the recommended temperature to mix fragrance into your melted wax is 185 degrees.
As soon as you remove the melted wax from the heat source, it will begin to cool. Adding fragrance will also continue the cooling process. If you add fragrance when the wax has cooled below 180 degrees, you risk the possibility of poor cold or hot throw.
The pouring temperature (the temperature at which you pour the fragranced wax into the container) will depend on the type of wax you're using. See manufacturers' directions for details.