Two computers with two versions of Unity and one license

With Unity 4 it is known that you can use the license also for Unity 3.
My question is: If I have a Unity 4 Pro license can I install it in two computers and in each computer install Unity 3 and Unity 4?
I ask this becaus in the oficial web page that talk about multiple versions of Unity don’t say anything about the licenses:
http://docs.unity3d.com/Documentation/Manual/InstallingMultipleVersionsofUnity.html
I’ve installed in a single machine Unity 3 and it asked for the license. I’ve installed then the Unity 4 and asked for the license again. I would like to know if I’ve used the two activations or I will be able to do the same in another computer with the same license.

Thanks

Your one serial can be used on any two machines. The version of Unity is not considered when you make these activations. So, yes, computerA can have 3.x and 4.x on, and computerB can have 3.x and 4.x.