Who it's for
The bell is not the end of the ratio.
School-age care is a different room with a different license line. It is still child care. The bus being late does not make the list optional.
Children arrive in a group when the bus arrives, not when your schedule hoped. Count that moment. A school-age ratio is often wider than preschool and still finite. Homework time is not unsupervised time unless your rule says it is.
The adult who picks up at 5:30 may not be the adult who does morning drop-off at the elementary school. The child care list is the one that matters in your building.