Yes, so "per capita" literally means "per person" in attendance.
So going into an Assembly day, they dont know what the actual attendance will be. They have a pretty good idea..... That's part of the reason they take a "count" about an hour into the program. They then announce just before lunch what the attendance is.
Lets say for example that the attendance for the morning program was 1,000 people (yes, they include small children, and babies). Then, magically, you will note that the "expenses" for the assembly day will be right at about $11,000. No mention of actual expenses or any type of breakdown. That is the amount that they want to see in the contribution boxes, period. No matter if the hall is paid for, and has been for years!
The congregants are NEVER told that the amount they have to come up with is just a general "give us your money" amount dictated by headquarters.