The part about Assembly Hall fees probably makes the least sense. It's a building the Society owns, usually paid off, and they charge their own members exorbitant fees to use it. It's often even cheaper to use an outside venue than one of the JW's Assembly Halls.
In my own experience, the assembly hall rental was closer to $9000 a weekend, but I believe that has to do with the number of publishers using the hall. If I recall correctly, the Society charged $3.25 per publisher per day for Assembly Hall rental, as of the early 90's (probably higher now). So, the fee would be much higher for larger circuits.