I think that average insulin needs depend on many things, age, exercise levels,diet , gender etc An adolescent boy in the middle of a growth spurt probably requires more energy, more carbs and therefore more insulin
As I dose adjust, my bolus insulin requirements are dependent upon what I eat and vary from day to day, my basal less so though it varies according to exercise levels. At the moment I eat about 150-160 carbs a day, take about 40% basal, 60% bolus and have a daily dose of about 24 units. I'm very happy with that. I don't need to restrict carbs unduly and hence do not have to adopt a higher protein or fat regime. I have a low HbA1c.