sorry but this doesn't answer my question?
You are right.
The serial key is valid for only 2 activations.
But if it is a volume license then the activations can be done as per the licenses purchased for that product.
how do we tell if it's a volume licence?
also if machines just have only this installed:-
what is this? is this still the full suite of Adobe acrobat Pro 9 as it states it's an add-on??
This serial number could be part of creative suite 5, so if you in box the serial number to me or Sheena, we can check the serial for you.