This article doesn't reveal much because it confuses 2 different scenarios:

1. The research result that a small amount of offtime, e.g. "In the Boston Consulting study ... guarantee each consultant one uninterrupted evening free each week", "can yield unexpected on-the-job benefits"

and

2. Examples of employees taking much longer times off, e.g. "staffers are expected to leave in time for dinner" (presumably every work day, and probably only 5 work days per week), and ""wellness scorecards" to track whether employees are working too much overtime"

Without diminishing the importance of prioritisation, the article doesn't reveal anything about offtime any longer than a very limited "one uninterrupted evening free each week".