Insulin after VSG

Could someone tell me how their surgeon determined how much insulin to send them home on after having the sleeve surgery?

I got my last dose in the hospital and never needed it again , 6 months ago I got off my last diabetes meds my a1c has been 5.6 with no meds

I was taking 15u of Levemir pre-op and they left me on the same dose. My GP told me to check my fastings every morning and once they are consistently under 100, I should call and they will start lowering my dose with the end result being me coming off of it completely.