Yes. The number of sites listed for your plan, is the number of sites allowed in your account at any time.
For example, if you are on our 2017 Team plan you can have a total of 30 sites in your account.
If you have used all 30 of your sites, you can either delete unused sites to create more space, or speak to your Account Manager about an upgrade.
You can always email firstname.lastname@example.org if you have any questions.