Complex sentence: The stores within the plaza are free to operate their own hours so that by 10:00 to 10:30 many stores are not yet open and by 19:30 to 20:00, many stores are already closing down.
Split into simpler sentences: The stores within the plaza are free to operate their own hours. However, by 10:00 to 10:30 many stores are not yet open and by 19:30 to 20:00, many stores are already closing down.