You could be working in two different applications on two different computers, going back and forth between them.
You can install any of the applications that you wanted to use on either of the computers but still only on two computers overall.
Hope that helps,
That was very helpful.
David_B, I am still a little confused by your answer. You said "going back and forth between them", but the question was if you can use them at 'the same time'. So for instance, lets say the Primary has Photoshop on it and the secondary has Encore, can a user be using photoshop at the exact same time as another user using Encore?