Pacer adjustment calories

hellllllen

can anyone please shed some light on my ignorance and general confusion..
I recently started using MFP on my iphone in conjunction with the step counter app Pacer.

As a waitress that has a short cycle to/from work as well as doing limited cardio at the gym a few days a week, on average I take about 9,000 steps a day according to the Pacer app this is giving me hundreds of extra calories a day for example between 800-1000.

Recently i've been eating mindfully between 1,500/2200 (depending on how I feel, if my weights staying the same as i'm trying to find a healthy balance in maintaining my current weight, if i'm eating in restaurants ect) So when considering the extra pacer calories, some times once i've logged my days food and find I have plenty of calories left that Pacer has given me?!?

What do these calories mean, Am I meant to eat them on top of my MFP daily goal, will I still lose/maintain weight if I do or will I start to gain pounds?
Thanks