Hey all, I am a 33 year old male currently weighing 187 lb. My goal is to lose 20 lb in the next 4 months, so between about 1 pound and 1.5 lb per week. I currently put in that I am lightly active and it suggests that I eat 1660 calories per day. However I'm just not sure if lightly active is accurate for my situation. Here it is:

I work from home and I'm in meetings all throughout the day and I am almost entirely sitting for usually about 6 hours throughout the work day. Which makes me feel like I am "not very active." However my Fitbit tells me that I have walked 16,000 steps per day on average throughout the last year (helps to have a dog) though I don't walk her particularly quickly, and I have been running between 15-25 miles per week through 3-4 runs/week and do full body 45 minute workouts at the gym 1-2 times per week on average.

With that in mind, feeling like I'm actually a pretty active person outside of having a desk job all throughout the day, how can I account for a 30 lb weight gain throughout the last 6 years? Well it must be that I am just eating too much food and have slowly been eating more and more liberally (over time increasing the regularity of yogurt smoothies, chocolate, baking cookies and pizza, eating out more often now that I've got a better income.)

So I really want to make sure that I am adjusting and eating the right amount of calories that would best set me up to be healthy, be able to run and work out with enough energy, and to hopefully lose 20 lb in the next 4 months.

Reddit, does 1660 calories sound like enough for me or do I sound much more active then "lightly active" and need to be eating a smaller deficit for greater success? / how many calories do I add back in for exercising, and is 20 lb in 4 months reasonable goal granted I do have skills in cooking and knowledge in healthier eating.

Tl;DR what activity level do I have if I work at a desk all day but walk 16,000 steps a day and working out four times a week (running or weight lifting)?

Edit: clarity