Wow! What kind of exercise do you do? I typically don't get better than 450-500 burned, 600 once on a long run! I'm jealous!
I've heard different opinions on this question - some say eat back some or all of your calories burned to keep yourself at the 1255 loss goal, some say don't. I did up my protein on days of heavy exercise and typically kept my net calories around the 750-800 range. Found that if I got way low I felt worn down and tired. I didn't eat back all the calories from the exercise.
For the most part, when my target was 1300 I ate 1300 calories and any exercise was just extra, but i didn't own an HRM until recently so didn't know for sure how many calories I was burning....