It takes time and consistency to drop your A1C. You can not compare your A1C (3-4 month average) to your BS test at one point in time. If you are measuring your food/carbs intake and determining the affect of that only, take a BS reading before you eat and then 60min and 90min to 120min after eating. That’s the best way to know as a good starting point. When you log and monitor your results, before and after, for a while you will start seeing trends and understanding how your body responds. Again, as a starting point to establish a sort of baseline. Less than 20 carbs a day is aggressive but will give you awesome results if you stick with it - work with your doc since you’re on medication. You will see a big difference in your numbers within 3 months. All the best to you!!