isn't it so you know how long to fast for?
we need to fast 6 (or 9, depending on church) hours before Holy Communion, so if we know when it was, we can enjoy that last glass of water 6 hours before.
in afternoon coptic liturgies, the times are often advertised like: 'liturgy 7-9pm', where 9pm is the Communion time, not the finish time.
at least, i hope it's not to deliberately upset the natives, who love to know when things finish and plan their arrival at home (a very non egyptian concept)!
so people will fast from 12 noon (we do 9 hours). of course there are a few who are really capable of fasting that will fast from midnight, but that is not the majority of us!