From that article, "To further investigate, we can try to see if he worked on weekends or weekdays: was this a hobbyist or was he paid to do this? The most common working days for Jia were Tue (86), Wed (85), Thu (89), and Fri (79)." That makes it more likely this work was done during working hours; someone doing things outside of work hours would be more likely to produce the same amount (or more) on weekends and holidays.
