You don't have to choose!
Camio counts the number of concurrently recording cameras on your account. So as long as the number of cameras recording at the same time doesn't exceed the number you've purchased, you're fine.
For example, let's say you have 3 cameras total:
If you subscribe to Camio Plus for only 1 camera, then record only with 1 camera at-a-time. You can even switch recording between the Frontyard and Office cameras throughout the day - like recording Office when you're home and Frontyard when you're at work.