Gestational Diabetes based only on fasting numbers????

Anyone else diagnosed as GD based only off their fasting numbers? My typical fasting numbers range from 90-105 with an average of about 98. All of my post prandial numbers are amazing. Baby is measuring right on target for her gestational age. I eat very well and exercise a lot. They want to put me on insulin for having fasting numbers barely above range. My average 1 hour post meal is right around 105, but also ranges from the 90s-120(if I eat a lot ). I have maintained my current numbers and am at 33weeks and 1 day. The lack of clear cut evidence based diagnostic standards is unbelievably frustrating! I have a friend who has far worse numbers and her doc is perfectly content with her diet control measures.