those seats paid for themselves after just 2 games and it still took 3 months of the football season to put them back in.
It's highly unlikely they paid for themselves after 2 games. There are a huge number of factors aside from the direct cost of a physical seat to take into account, which you've evidentially chosen to ignore. Planning, Installation, extra staffing of the seats, any permits or approvals that are needed.
Thats before the extremely simple fact that not everyone going into the new seats is a new customer or a customer that would otherwise not have attended, they very possibly could have been attending in other stands.
Another number just pulled out your backside, and you wonder why people don't take you seriously.