The last assembly I went to we were quoted $11 per publisher as the rate the society had set.* So $10 per publisher on top of whatever was received at the assembly seems really high. It must vary from region to region - do you know what the supposed cost of the last assembly was and what the announced deficit was?
*I've posted about this on here before but it always cracks me up to think about. The man that gave the accounts report was from my former congregation and is well known for being a little "simple" to put it nicely. So he gets up to do the accounts report and announces that the society has seen fit to raise the per-publisher rate of our assembly that they use to determine the assembly's cost. Because they had raised the cost to $11 per publisher, and there where x publishers the cost we were expected to cover was y. The way he explained it, he made it clear as day that the "expenses" of the assembly had absolutely nothing to do with the actual cost of maintaining the building and turning on the lights, etc. I don't think this is typically common knowledge among JWs, and something tells me he won't be doing the accounts report again.