According to the natural history of Type 2 DM there is a progressive fall in beta cell function and that is the reason that many of these patients need Insulin 8-10 years after diagnosis of the disease. Recent research shows that its better to start insulin during early phase of Type 2 DM rather then waiting for complete exhaustion of beta cells. This theory of beta cell preservation seems to be correct. By using insulin glucotoxicity comes down. Glucotoxicity means suppression of beta cell function due to high blood glucose levels.
As per data provided by you it seems you have a perfect control and you can start reducing the insulin dose and introduce medications like Amaryl or Diamicron. Problem with high dose of insulin is hypoglycaemic (low sugar) attacks and weight gain. Another type of insulin which has a 24 hours action and does not cause weight gain and hypoglycaemia is Insulin Glargine (Lantus). For you best will be Lantus 30 units at 8.00 hrs plus Amaryl 2 mg and Glucophage. Keep getting your A1C levels every three months and keep it below 7%.