Interesting about the <85 reading, but I am guessing this is for people who are not above 99 to begin with? I rarely get below 100 on a doctor's fasting glucose test, and when I do, it is probably because I am rapidly on the way to hypoglycemic, when I shouldn't be waiting for a test before I eat. I see from the Freestyle manual that finger is still the most accurate, although you could probably get away with arm for fasting levels, their cautions seem to be primarily for when your levels are changing quickly. Arm sounds like a much more pleasant place to poke, when you use fingers 4x/day for weeks on end, your hand becomes a giant papercut.
I had gestational diabetes a couple decades ago, and I’m sure the rules have changed. Even now there are differences in guidelines about what's normal glucose. Based on what I saw online, it appears that after a 75g sugar load, a normal reading is <140 after 2 hours, and that the same levels are applied to meals, although there's a big difference between what people eat for breakfast and dinner. There also seemed to be disagreement between the endochrinologists and the ADA. I've read normal levels are between 70 and 150, but there are differences on that, and variation by population and age.
JBird, did you decide your really low readings were errors? From what I read, readings <70 (some say <50) generally suggest hypoglycemia, especially if you have symptoms. And unless it’s at a crisis point, the control for hypoglycemics is a lot like that for hypergylcemics, a major focus on balance and avoiding simple carbs.
To control diabetes by diet, everything is carefully balanced. When I had GD, I balanced carbs/proteins/fats, every single time I ate, big meal or snack, all the same. A serving of carbs was no more than 15g. Take your Fiber One at 25g, add almond breeze and I hate to think where my readings would be. There was no such calculation as 'net carbs,' every carb counts. I avoided refined carbs because they release sugars so fast, so it was mostly complex carbs. I could never have just oatmeal at breakfast, and cereal plus milk is not balanced, either. Oatmeal and cottage cheese is closer. Protein at every meal, with a bit of fat to slow digestion of carbs.
Hypoglycemia can cause uncontrolled hunger, after the low glucose crisis is over. When I started platinum calories, I went hypoglycemic and overcompensated. And will continue to overcompensate whenever I let myself get too hungry. Except, I will plan ahead for next time.
A person with normal glucose may get more consistent readings from a meal, but when I tested, I could eat exactly the same things and have wildly different numbers the next time. It helped when I found consistent patterns of what spiked my numbers every time, but often it was a mystery. The GI research seems the same way, ok as a ballpark number, but the variation in testing between brands, or within brand at different times, is huge.