A1C tests and fasting

Normally my DR asks me to fast before I have my bloodwork done. A few weeks ago I went in to have routine bloodwork done to check my thyroid levels (I take levo and needed to be adjusted) and my DR decided to go ahead and do an A1C test as well while we were already doing bloodwork. This was unexpected for me so I had not fasted or anything and had already eaten breakfast and lunch. So, I get my results back about a week later and my A1C number was 6.4…lower than it had been 3 months prior at 6.7…I’m wondering exactly how accurate that number is since I wasn’t fasting, and frankly haven’t been keeping up with my health plan as I had been either. Does fasting make a huge difference? Also…I really haven’t been exercising or eating as good as I was…how could the numbers be lower? I know its just an average, but still…I wonder…