The CSS4 license wiki states:
Q: How many computers can I use a node locked license with?
When generating a node-locked license file you can specify 2 MAC addresses (hostids). This allows you to install and run CCS on 2 machines. The license terms state that you cannot be using them at the same time. The purpose of this is if you have a work and home machine or an extra machine in the lab that you need to install CCS on. If you need to run on multiple machines concurrently you should purchase more licenses or consider a floating license pack.
Is this also valid for a CCS5 Node Locked License?