I was an OC and DC before becoming a HC. My first year as HC, I call both sides of the ball....we went 5-5, not bad for that school. I fired most of my inherited staff that off season and hired a 5 young coaches that called the game under my supervision, but allowed me to become more of a walk around coach, over seeking every aspect of the team and staff. We went 34-4, the next 3 years. I believe a HC, should not call either side of the ball and focus on the big picture. The flow of the game, clock and time out management, player substitution etc. You can see who is loafing, you can tell the OC to run the ball and allow your defense time to rest and the DC time to adjust etc.....and coach with feeling and not computer analytics......any word that starts with anal, doesn't belong in football.