Subby,
Something a lot of people are not aware of is that the level and duration of injected insulin action is very variable. Even with the modern insulins, intraday variability of action is 20%+. It means that 10 units of insulin can have between 8 and 12 units worth of effect. That is a huge difference. And it is a major cause of blood glucose volatility. Some people have more luck with it than others. But if this is a problem for you, the best way to deal with it is to minimise the amount of insulin you are using. A 50% reduction in the amount of insulin you use, for example, will eliminate 50% of the volatility you have been experiencing.
How much carb are you eating? The easiest way to reduce blood glucose volatility is to minimise carbohydrate consumption. The less carb you need to cover, the less insulin you need to inject. I would reduce carbs to below 50 grams a day until things settle down. And they will. You can then consider systematically re-introducing some carbs in amounts and at times that are the least disruptive.
I have ended up eating virtually no carb for breakfast (because of fierce insulin resistance), 15-35 grams of carb for lunch (I am sensitive to insulin at this time of day) and about 10 - 20 grams of carb with supper (depending on what the family eats). I have reduced my total daily insulin dose from 55 units to 35 units. And, for the most part, my blood glucose is extremely stable. Achieving this was very important for me because of my history of Eplilepsy. I don't have seizure inducing sudden hypos anymore. And my blood glucose doesn't often go over 10mmol/l. I also used to have extreme difficulty bringing high blood sugars down, and I know what it is like!
