A single Neural DSP license can be activated on 3 different computers at the same time as long as the same iLok account is used on all of them. Licenses can be deactivated from computers that are not in use and transferred to other devices. This process can be repeated indefinitely.
Notice that licenses and activations are different things. When you purchase a Neural DSP plugin, you get a single license with three simultaneous activations. Activations are managed on the iLok License Manager app.