@NormanDunbar @afewbugs I think this is one of the most typical behaviors.
(Stipulating that the CS undergrad population might have a disproportionately higher number of neuro-atypical people...) I give my students six days to take exams at the testing center. Not including final exams, here's what I see every exam, every semester: About 2/3 of the students will take the exam on the last day. Of those, about half will take it after 5pm. Of those, about half will take it between 8:30pm and 10pm, when the testing center closes.
As much as "ripping the bandaid off" makes sense to put an unpleasant task behind you, most people avoid unpleasant tasks until they can't anymore.