The congregation where I was going had meetings for field service at 9:00 am, weekdays and Saturday. To be at the meeting for field service during the week required herculean effort if you had get kids off to school and drive to the very rural KH. When I asked why they met so early, the elder told me the older ones liked the meetings at that time. The older ones are very inflexible, I've noticed, when it comes to JW things. At another cong. I attended, the Service Meeting was at 7:00 pm. The elders were constantly harranguing everyone about getting to the KH on time. So many attendees worked 30-80 mi away, they forced a vote to have the meeting at 7:30 pm. The results were split almost evenly, but the old ones, who gave very few parts, were retired and had no kids to get ready, all voted to continue the 7:00 pm meeting time. The elders continued to beat the R & F about being there on time, and the hall always started to fill between 7:15 - 7:45.
By the way, meeting for field service before 9:30 am should be against the law. Who wants a bunch of religious weirdos knocking on their door on Saturday morning, at 9:20 am...its just criminal!