Not exactly. :) The Pro (or rather Commercial license, as we call it) is good for as many PCs as you purchase the license for.
If you purchase the license on a "per remote PC" basis for, say, 100 remote machines, then you can install and register the Host on 100 remote machines.
If you would rather prefer to pay on a "per operator" basis, then you need to pay only for the number of admin machines (Viewer machines) that will be working simultaneously. The number of remote installations will be unlimited.
Right now the Host can automatically "call back" the Viewer by its IP address or DNS name, if you set up a call back connection (see Callback connection). Is that what you mean or do you mean something else?
We are planning to add a fully-fledged address book sync (and also a web account too) in one of the next releases. As for rights management for address book records - that's also a good idea. We'll see what we can do in this respect.
UPDATE: We have simplified our licensing even more. Now if you purchase a commercial license you only need to choose a preferred pricing model: per operator or per remote PC. Program functionality is the same for both pricing models (i.e. full functionality of Remote Utilities).