it is just a check i run on my and internet diabetes numbers.
it is the A1c converted to mg/dl minus the reported FBS times 4 because your highs should only exist 1/4 of the time, and that number added to your FBS may indicate the average maximum blood sugar. maybe at least in your case the factor should be 3 instead of 4 but that would still show about 166 off hand i think.
you seem to still have a lot of your pancreas left.
also if your pancreas is storing insulin and dumps it as a phase one response then your peaks will be flattened and the formula will be way off but many T2's run on an exhausted pancreas and their peaks will be higher.
i purposely inject more insulin than necessary so that my pancreas will store it. that gives me a flatter base line and reduces my peaks if i consume less than 20 carbs per meal. that way i got an A1c of 5.9 even though my FBS was around 120 mg/dl.