There is a fixed amount, $ per publisher, for each person belonging to a congregation assigned to that assembly. Last I remember it was $10 a head.
What most likely happened is that they shuffled the circuit around a bit. Likely there were 1100 - 1300 publishers assigned to that assembly in the past, but now the number assigned is around 800.
Add in kids who are not yet publishers and you get an attendance of 932.
By the way, the $10 (or whatever) per publisher is supposed to be a hush-hush, top-top-top secret. So you didn't hear it from me