A Calorie intake double check..help understanding.

I'm a little confused. What is your MFP goal before you log any food or exercise?
Where did you get the 3,378 calories goal?
Since you have about 6 lbs to lose according to your ticker and you are within a healhty BMI, it is extremely unlikely that should be your calorie goal.

Also, what did you choose for a weight loss goal? With 6 lbs to lose it should be no more than. 5 lbs a week.

But to explain the change - MFP expects you to log exercise because ven though you chose moderately active, that does not include exercise. That is daily life, like your job, etc. MFP wants you to log exercise and eat those calories back.

"Isnt the idea of asking for activity level a way of getting your BMR? "
No, BMR does not include exercise. BMR is what your body needs just to survive, before you even do any regular daily activty or exercise. Also, as I mentioned above, MFP does not include exercise in their formula until you log it.

You're not suppose to add your BMR to your calorie goal, and be careful with your daily activity level. If you're at moderate chances are you shouldn't be adding activity.

Personally, having my calorie budget adjust every day is annoying. I set my calorie goal at the calories required to maintain my goal weight, then I only log exercise before bed and do not attempt to eat those additional calories.

For example: 135 lbs x 11 (for sedentary person) = 1485 daily calorie goal. Then anything you do physically would just add to your weight loss.... just be careful to keep that loss within safe parameters.

Good luck!

P.S. I just noticed my ticker for first time... I don't know why, but it doesn't show my actual loss of 23 pounds.

AAAAAaaaaaaah. Forget that 2000 calorie thing. The FDA has no idea how tall or how active you are, and so they list 2000 calories as the "average" diet. For each of us, individually, it will be somewhere between 1200 and...errr...I've seen people eat as much as 3500 calories per day if they were hardcore athletes.

For your own caloric intake, there is BMR, which is the base metabolic rate. This is how many calories your body would burn just to keep you alive, if, for instance, you were in a coma and didn't move.

Then there's your TDEE...this is how many calories your body burns on an average day, taking into account your average activity level in your day-to-day activities. It includes your BMR, plus the extra calories you burn at work, your leisure activities, etc. So, for example, if you were a waitress you would burn more calories at work than if you were a copy editor sitting at a desk all day. If you run around with your kids all evening, you'd burn more than if you sat on the couch and watched TV all evening.

Your goal should be set something like this: Either put your info into MFP and let it set your goal for you, or go find a TDEE calculator, get your TDEE, and subtract something like 10%, or 500 calories, making sure that you never dip below 1200. That should be your goal.

The 500 calories is arrived at by this: a pound is 3500 calories, so if you want to lose a pound in a week, you should eat 500 calories less per day than you burn. That puts you at -3500 calories after 7 days. The 10% is often more useful for larger people, because 500 calories is a smaller percentage of their TDEE, and larger people are able to lose weight faster.

Now, when you exercise, you log the exercise into MFP and you can eat those calories back. So, for example, if your goal is 1400 calories and you burn another 200 calories doing cardio, then you can eat 1600 calories for the day. Your goal of 1400 calories in this example is already taking a deficit into consideration, so there's no need to make the deficit even bigger by not eating your burned exercise calories.

Does that make sense?

You are making this WAY too complicated.

Forget the 2000 calories. That's just an average, and aside from that it's an average for maintenance, not for weight loss.

Put your stats into MFP correctly. Tell it you want to lose half a pound per week. Set your activity level correctly (don't choose sedentary if you think you're lightly active). Then eat the amount MFP tells you, plus half of whatever you burn through exercise.

Make sure you're logging accurately, with a food scale if possible, and readjust in 4 weeks if needed based on your results.

You are making this WAY too complicated.

Forget the 2000 calories. That's just an average, and aside from that it's an average for maintenance, not for weight loss.

Put your stats into MFP correctly. Tell it you want to lose half a pound per week. Set your activity level correctly (don't choose sedentary if you think you're lightly active). Then eat the amount MFP tells you, plus half of whatever you burn through exercise.

Make sure you're logging accurately, with a food scale if possible, and readjust in 4 weeks if needed based on your results.

^This. Especially the bolded. Put your stats in..follow the directions and use the tool as it is meant to be used.