Virtual Computers - snapshots and clones - how many licenses?

In reading this forum, there is a post where Avast! says you need a SEPARATE license for each virtual computer.
in http://forum.avast.com/index.php?topic=34346.0

Quote from: loftrat on April 03, 2008, 06:49:28 AM
c) If I need additional protection does the Avast Pro licence allow me to install Avast Pro within multiple virtual machines on the same physical machine?

I’m afraid not. Sorry.
You can use the Professional Family Pack though.

However this doesn’t go into enough detail covering multiple snapshots and clones of a single computer. Under VMware Workstation you can have many snapshots of a single machine at different times, and also you can clone a computer. I have 5 virtual computers - XP-Pro 32bit, Vista Ultimate 32 and 64 bit, Win7RC 32 and 64 bit, running on a Win7x64 host. After I set up each VM install all the Updates and install Avast, I take a clone and store it as a static base for future clones. I also take a snapshot of each computer before a software install. I may end up with 10-15 clones along with 10 separate snapshots of each clone. After a week or so and I feel that the software is stable I do delete the snapshots, but then I re-clone the computer to keep the VM’s hard drive fragmented. What does all this snapshots, clones, and mostly unused snapshots and clones do to my license count? For the most part I don’t go backwards unless I start getting BSOD’s. Thanks in advance, Lvdata.

edit - --keep the VM’s hard drive DEfragmented-- oops…

I’m almost sure you can use the same license key for different snapshots of the same virtual machine. I’m not that sure about clones…