Can I use a single account in more than one display at the same time?

Nope… sorry!

You can use 2Shapes products on any compatible device, at any given time. For example, you could use the same 2Shapes account in your workshop’s computer, your tablet, and your home’s laptop.

But, if you need to use a 2Shapes account on multiple devices at the same time, the best option is to Upgrade your plan.