I agree with BB that it all depends on how your body handles the carbs that you put into it.
I have had to go extremely low carb (less than 20g a day) to reduce my bg from just hitting diabetic levels, down to below pre-diabetic levels.
Other people who post here have reduced their HbA1c from over 100 down to pre-D levels by just dropping to 130g carbs a day.
But then, it all depends on where you started, too. I mean, I had been low carbing for years, the people with higher numbers and quicker drops may have been chomping on significant carb intake for decades...