This calculation only applies to people with no residual beta cell function. There are other noise factors too, like level of carbohydrate consumption, insulin delivery method, age, hormonal activity etc. This is why there is variation around the norm. When your beta cells finally pack up, yes, you can expect to see an increase in exogenous insulin requirements towards this benchmark. But if you stay in shape and get lots of exercise, you should continue to be relatively insulin sensitive. My number works out to 0.47 units/Kg, but I have been T1 for 30 years and my beta cells are completely dead ....
