I don't know if there's consistancy in the meters being higher or lower in accuracy. I've only read as you have that there's a +/- 15 to 20% accuracy accepted in the industry. There are so many factors involved like, humidity affecting test strips, quality of blood bead (too small..), individual meters, even meds and supplements we take. I have four Bayer Contours, one is older and takes 15 seconds for results and it always reads much higher than my 3 newer ones. The best way to check for their accuracy is to bring your meter in to the lab when you're having your blood tests done and use your own to test right after they do their test. When you get the lab results, compare them to your own meter's. You're wise to be aware of your blood sugar, especially if you have diabetes in your family and if you are carrying around extra weight (and I don't mean the laundry basket). 
A low or lower carb diet will help you control the blood sugar and lose some weight. Also, doing some sort of regular exercise will help, like walking. And - don't forget, there are no dumb questions here.
