I was looking at the Airbus 380-800 and creating a test configuration for it.
On the page for the plane, capacity is listed as 853. When you build a configuration, the certified capacity is listed as 538 and that’s the maximum number of seats you can actually put in the plane.
Attached is a screenshot. In the top section it shows the certified capacity as 853, in the cabin setup area it shows it as 538.
It also lists capacity as 853 on the Aircraft Manufacturers page, which I am attaching a screenshot for as well.