The answer, as usual, starts with 'it's complicated'...
High BGs are cause by (either/or) a combination of not enough insulin being produced *or* an inability to use it properly.
There is a school of thought that rapid weight loss shortly after diagnosis to achieve a normal BMI (Well Done!!!) may allow the pancreas to recover a bit - but a bit controversial, so a bit more insulin will help, irrespective of diet.
The greater contributor, in your case, is more likely to be a big improvement in the way your body actually makes use of insulin, due to reduction in the amount of fat in your body, and also an increase in effective muscle mass if you've been doing sustained exercise.
So, while an increase in carbs would (for almost all people) count towards higher BG and A1c, the improved 'performance' of your body is obviously enough to not only counter that, but also reduce both readings.
Most people (and I number among them) would suggest that a lower carb regime after you hit your final weight will be a help in long term BG management.
In the meantime, good luck and keep up the good work!
Mark