I believe that each key is allocated 10 activations without taking into account the consistency or sequence of settings. If 10 activations are exhausted, you can contact Microsoft to request additional keys.
A back (I have not checked it recently), msdn subscribers also had access to the online concierge chat. While Microsoft employees who worked in this chat room could not answer technical questions (clearly, given the breadth of technical questions to be asked), they could answer real questions about msdn subscriptions and software licenses and rules providing. I asked them if I can use my MSDN license key to install a copy of the OS for @home to work by convention, for example.
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