Dragon Medical is licensed by user, not by machine. So, if you purchase Dragon Medical Practice Edition for a single provider you can install it on multiple machines, as long as that provider is the only one who uses Dragon Medical. Dragon Medical Practice edition can be installed on up to 4 machines without a warning message indicating that you've exceeded the maximum number of installs for that license.
Dragon Medical 360 | Network Edition and the less popular Dragon Medical Enterprise Edition are also licensed by user. Neither of these products has a maximum number of allowed installs.