Net calories and exercises

From what I understand through study of the subject and personal experience it depends.

When slimming down you need to maintain a calorie deficit. You can do this by reducing calories and increasing exercise. Most calculations for burning calories are based on measurements done on athletes(around 8% bf) so when a machine says you burned 500 calories for your weight, it is likely that you with a bf of 20-30% burned 3-400 calories. The three problems that occur when limiting calories is maintaining proper amounts of micro(vitamins and minerals) and macro(carbs, essential fatty acids, protein) nutriends, loss of muscle mass(as your body metabolizes muscle at a higher rate, and lack of energy(which can demotivate you from working out and give you cravings). If you can push through the hunger cravings/lack of energy then your main focus should be to maintain muscle by eating proper micro and macro nutrients and performing resistance exercises.

When bulking up. You will want to maintain a calorie surplus. Hitting nutrient and protein goals should be easy as you can eat more. The main concern is eating too much/ too little. Gaining some fat during this is actually desirable. You can only gain about 1% of you weight in lean body mass(muscle) per month although you may experience more initially as your muscle swell with water for protein synthesis and ATP(energy) production. If you weighed 150 lbs. you might expect to gain 1.5-2 lbs. of muscle in a month however most individuals on a proper routine will gain 3-5 lbs. This is because of how our body priorities energy to be stored. If you only gain 1 lb. you are likely gaining only .5 lbs of muscle and .5 lbs of fat so you are loosing gains by eating too little. Conversely if you are gaining 5 or more lbs. you are likely eating too much and thus putting on needless fat. Maintaining a cardio routine is a must. A HIIT(high intensity interval training) routine has been shown to not only help burn calories but improve muscle strength and VO2Max(how much oxygen your body metabolizes when you breath).

The best option is to monitor weight/bf%. I would try to slim down to an 8-10% bf. then bulk until I hit 14-16%bf. This would result in a 2 month bulk/ 1 month burn cycle. People have different routines, but this seems to be pretty effective.

Are you calculating your exercise calories into your TDEE? I have my TDEE set to sedentary (which really isn't that sedentary), then I add my exercise cals after that.
Example.
My TDEE 1995
- 500 cals for 1 pound a week weight loss = 1495 ...this is my daily amount with no exercise and on a basic day of 8 - 10,000 steps.
So even at a 500 cal work out I still only top out at 2000 cals. (apart from a day of landscaping and that was a conservative estimate of 1500 cals ....man that chocolate tasted good LOL)

Your calculations seem right.

If you are only hitting 1000 cal net a day that is far too little calories, specially for a guy. Your basically crash dieting at that point. You will definitely lose weight, but when you run this extreme of a deficit you are also losing your lean body mass (LBM). That consists of your muscles, connective tissues, and even organs.

Now everyone is different to some extent and making all your decisions based off online calculators and expenditures isn't the best way to do this. You can find out really quickly how well a diet is working for you by testing your body fat % and figuring out your LBM. If you are running too large a calorie deficit your LBM will decrease along with your weight. Start worrying about your body fat % and not your weight dropped. Weight alone is a poor indicator of your training and diet routine.

Test your body fat % and then keep to a diet for a couple weeks and get it tested again. If your weight loss is all fat you have yourself in a good routine. If not, make adjustments as needed. Use your calculations as a starting point and custom tailor your diet based on your body fat % results.