Well, calculating how much you should eat per day to lose weight isn't all that simple. For some people, those calculations work, and for others with faster or slower metabolisms, they don't.
Use it as a general guideline, and then adjust it to YOUR body. So...try out the 1650-1700 calories for a week or two, weigh in, and see what happens. If you lose a pound or two per week, then it is the correct level for you. If you don't lose, however, then you need to adjust it slightly lower. If this is the case, try 1500-1600 for a week or so, weigh in, and see what happens again. Do this until you find the place where you are losing 1-2 pounds per week.
This is going to be the same whether you exercise or not...the only time you would need to add more calories, is if you are doing something super strenuous, like training for a marathon. For regular workouts, however, keep it the same.