Just because you are exercising, it doesn't make the 1250 calories that you actually eat turn into 950 calories.
Your exercise should stay separate from your caloric intake, or one can get confused. If you eat 1250 calories, that is what you eat, it doesn't make a difference whether or not you exercise for 4 hours or not at all-it doesn't take away any of the nutrition that your body took in.
The goal is to create a calorie deficit-burn more calories than you take in with food. Your body will have a basic amount of calories that it burns per day. You create the deficit to lose weight by A) exercising to burn more per day and B) eating less calories.
The formula for one person might be 1500 calories a day and 30 minutes of exercise. The formula for the next person might be 1400 calories a day and 1 hour of exercise. Everyone is different.
What you are trying to create, though, is an average loss of 1-2 pounds per week.
If you are eating over 1200 calories a day, and you have the calories and exercise amount worked out to where you are seeing a loss of this range, then you are doing it right.
Don't try to "take away" your exercise calories from what you ate.