Truth clearly lies in the middle. Maybe on average .. a workplace is a better concentration of means and dedication even though it's obvious that it's a very very inefficient place most of the time.
The truth lies in admitting actual productivity. He's claiming 0.68 or 5 hours and 26 minutes of productivity when WFH. That's a huge number to have both consistently and exceptionally. I bet the average person gets 2-3/day if they're honest about it.
Japan is also famous for its salarymen who will fall asleep at their desks to avoid leaving the office before their boss. Time in an office does not equal productivity.
The truth is almost never the average. (What's the average handedness of a population?)
But it's a convenient aggregate despite a likely heterogeneous population.