This is just off the wall but has anyone checked the voltage to the fixtures when they are on, but at like 2 am?
It sounds nuts but I have had problems with the utility supply hitting as high as 253V in the middle of the night at my own home. During the day the supply was an ideal 240-242V, unless it was hot out and everyone was running their A/C then the voltage would be around 230-235V) . I never had problems with any lighting or appliances in the house because nothing is ever on during the times the voltage was hitting 250V+, but when I notified the utility they were pretty quick to change out the transformer in front of the house.
Could something similar to this be happening at the church? Just a thought...

A.D