Reactive hypoglycemia, is a prelude to developing diabetes.
Some move on to diabetes, and others don't depending on their own genetics.

I really don't think you need 600mg of benfotiamine a day.
Once those enzymes get saturated with thiamine, then you can coast on a lower dose. 300mg or 150mg a day should be enough for most people. 150 mg is all I take myself.

If you don't FEEL the hypoglycemia, then it may not be an issue at all for you. But if you feel shakey and sweaty before meals then do lower it a bit.

Insulin resistance is the cause of the reactive hypoglycemia. It means you have too much insulin being secreted after a meal.
Fixing your diet as you have, should be doing good things for you.

The A1C is a measure of a type of hemoglobin in the blood, that has a glucose attached to it. It is a 3 month average of your blood glucose level. People with high spikes after eating will show that in the A1C. But lows typically are not predictable or illustrated with it. The A1C changes with race and age... so it is not comparable 100% to everyone equally. It is rather new, and as such is undergoing scrutiny for accuracy in the elderly or those of African or Hispanic descent.