If there is a time limit for taking the Quiz/Midterm/Exam between the open and close times, enter it here.
E.g. The Exam is open between 1:00 pm and 5:00 pm, but once students start, they only have 60mins to finish. As long as they start by 4:00 pm, they will have the full 60mins to write. However, if they wait until 4:30 pm to start, they will only have 30mins, being cut off at 5:00 pm.