BTW, as mentioned above by Mezonos Maven, Is the problem most pronounced in the morning, when the PS opens? Most Yeshivos and BY’s have different dismissal times than do the PS’s.
They do have different dismissal times and they also have different start times. PS usually begins at 8:15 – 8:30, while many Yeshivos start at 9:00. The older boys have to be there for minyan, usually earlier than PS start times. The older girls get out 4 – 4:30 while the older boys stay later than that, 5:45 or so, or even later, depending on the night.