This article explains the relationship between the license and the domain in PST Flight Deck.
When installing PST Flight Deck, you’re prompted to enter a License. The license contains domain information.
The domain information in the license is important for the PST Flight Deck Core server location. In other words, the Core server must be installed within the domain listed in the License.
On the other hand, there are no ties to users. Even users from domains not listed in the license can be migrated without any problems by PST Flight Deck.
PST Flight Deck collects information about users through a service called Active Directory Sync. In order to get information about users from other domains, it must run under the account that has read rights to other domains. Those domains don’t need to be listed in the license.