Hi, tThanks for contacting iToo Software and for your interest in our products.
A network license can be used from any computer in the network, but only one at time (or more if you purchase a license for multiple seats).
The license is needed to edit or rendering interactively (when Max is handled by an human operator), but not for non-interactive render modes as Backburner, Distributed rendering or Batch render.
So, if you plan to use the plugin in two computers simultaneously, you will need a network license for 2 seats. Instead, a single license will be enough if you use one computer to edit/render, and the other for network rendering only.
Please, don't hesitate to ask us if you have any doubt. You can find other common questions replied in the Purchase and License FAQ