If thats the case , hope your'e right.It's not uncommon to have a sunken lower tier that you can then plonk the main concourse at ground level. This gives more space and reduces the cost of the build as you only need the posh exterior on half or 2/3rds that is above ground.
If we have a 60k stadium it would still be the size of Goodison at ground level. (actually probably taller as the stands will have more rake)