1. the 1200 floor is a nutrient minimum [it's really hard to get all the nutrients you need in fewer calories]. your exercises calories do not come in to play there at all.
2. at 5'8" and 148lbs, you're already at a healthy weight for your height. if you can get a bodyfat number then that is going to be a better guide of what you have to lose than the number on the scale. but without that info, you're going to have to scale back your loss goals. losing 1lb per week just isn't realistic when you have so little weight to lose. you're looking more like topping out at 1/2lb per week or aiming for 1/4lb per week. when you don't have a lot to lose, you do have to eat pretty close to where you maintain, so it can take a long time to see results.
this is how your ranges are calculated. the short of it is that if you're burning about 2350 a day and you don't have a lot of weight to lose, you should be eating somewhere close to 2100 cals.
you can't really take a small part of your total burn for the day [your exercise] and compare it in any useful way to what you eat. you have to look at your total burn [your bmr + your daily activities + your exercise] and compare that to your intake and see if that leaves you at a deficit or surplus.