date_1 and date_2 both happen to have times of 09:30
date_3 has a time of 10:30. date_4 has a time of 9:30
The internal logic is
first_date : 1 : last_date
and then filter down to the business dates.
When the start time is 10:30 the generated times will all be 10:30 .
Note that date_4 itself will be excluded, since it's 9:30 time is after the 10:30 time of the starting time.
