The point is to have a party for a team of 12, they were spending $200. It does not matter whether it was all eaten, they spent that amount for the team.
We can thus assume that if all teams did something similar (why would you only allow some teams and not others), the dollars add up and that is how you look at it from a company perspective. Not the one team’s spend, but the overall spend.
So about $16 per pizza.
There's no mention of how many team members were having pizza. Probably not one each though.