Over goal, under BMR?

Alright, so I have the MFP app on my phone and I track, religiously, the stuff I eat with it and what I do as far as exercise. I have it set to lose 2 pounds a week because I want to be 200 by mid-May (I'm 218 now and have come down a considerable amount). The only problem I have is this: I'm a 19 year old boy, so I eat and stay hungry. I've severely cut down the amount of food I eat, but the MFP app has me saying to lose 2 pounds a week I have to eat 1,690 calories or less per day. Even for me eating less and healthy, this is INCREDIBLY hard to do and most days I do end up going over to around the 2000 mark, and I also exercise (walking/lifting weights) and my job, while not the most demanding thing in the world (cashier), burns around 2 calories/minute for my weight and size. So a little 4 hour shift still burns ~480 calories.

Anywho. I got to checking: How in the world am I still losing weight if I'm over eating my calorie goal. Turns out, my BMR is somewhere around the 2,500 calorie mark for my age, sex, size, activity level, etc. So... my question is... if I'm still eating less than my BMR, but not as low as MFP wants me to... will I still get the same results, just possibly slower?