Is paying 400 dollars to repair the church hammond too expensive? Like reconnecting drawbars, fixing the driver in the leslie and the tremolo switch and a couple tubes?
I paid $200 for a regular annual servicing and tremolo switch repair.
For what you are having done, it sounds like your price may be decent. If you are not sure about your quote, I suggest you get a second opinion from someone in your area who could look at your organ. There are not many people who service Hammonds, so you may have to go with the initial quote you were given.
Keep your intruments serviced annual. Churches don't take care of their instruments. Even after something breaks (keys, etc.), they use them until they can't be used anymore.