Why does server maintenance have to take place at 6pm?

I manage the OMG radio station, and we have a real problem come 6 in the evening when the server maintenance occurs. I do not see why this has to happen? From what ive heard its an automated process so could it not feasibly be done when people are not in need of the service?

It affects are live stream, and people getting in contact, some of our most popular shows begin at 6 and the listeners get annoyed because their listening becomes interrupted. 
Is there anyway at all that this can be changed?
Investigations will be initiated by Information Services into the problems being experienced by your listeners.  As part of this investigation the scheduling of routine maintenance activities will be reviewed.