The same thing happened to me.
When I divided my meals into 5 (instead of 3), my numbers dropped. When I split my exercise into 3 shorter sessions (instead of 1 long one), my numbers dropped. I really didn't change anything too drastically (different carbs, but not fewer carbs)- but all of the little changes added up to nice drops in BG levels. I have beeen doing this now consistently for about 8 months and my numbers and A1c have stabilized in the 75 - 95 range (fasting, pre-meal, pre-bed) with 100-110 after meal readings (lower 5's for the A1c).
I have been traveling for the past 10 days- my schedule has been shot to he$$- my meals have been a big departure from my normal routine- but I exercised every day, and drank water like a camel at an oasis- and my numbers were as good as at home! I'm guessing that once your body gets used to a certain range, it tries to get there and stay there-
I also noticed that while it took me a good 4-5 months to get rid of carb cravings, it only took a few meals with slightly higher carb counts for me to begin thinking about what carby things I can eat now that I'm back home again. Thankfully, I am too tired to go to the grocery today or I might give into the temptation!
Congrats on your better numbers!
sandy