Syncing with Fitbit Question

Does anyone use Fitbit and sync it with MyFitnessPal? My daughter got me a Fitbit Zip for my birthday. I have it synced to MyFitnessPal. I don't understand how it works with MFP though. It is treating the steps I walk as if they are calories consumed, not used in exercise. So if I walk more, I have to eat less to reach my calorie goal? I don't get that. Am I doing something wrong? It does counting my steps on MFP as exercise, so I enabled Negative Adjustments in my MFP settings. Now it counts them, but as I said it reduces the amount of calories I have left to eat. Usually exercise increases them. Not that I want to eat more, it just messes up my daily number and looks like I'm eating more. Any help with this would be appreciated.