I fly a fairly normal roster of flight operations, as well as manage and administer to all of the Performance Engineering work for one of our company's divisions (I do not do P/E work for my "own" aircraft). The latter generally takes up more time than the former, although there are (thankfully) sometimes lengthy periods of 'steady as she goes'.
I've found no conflict between the two, and one does become accustomed to 4 hours of sleep per day.
I suspect (but cannot be sure) that
Mutt has a similar mix of flying and P/E duties.
Regards,
Old Smokey