HELP NEEDED ABOUT MY FITBIT

I love, love, love my fitbit.....but here's the question.....for example rode bikes twice today....put it in like it said to....it showed I burned let's just say x amount of calories......then I see now that I have a fitbit adjustment. Does that mean that I did not count as much as it should have.....because I am positive, that I burned more than 198 all day.....just curios.... Thanks for any help!!!