Need help with calorie intake

So I recently got out of the military and have found myself steadily gaining weight. I have been into weightlifting the past three years, from about age 19-22. I've always had trouble losing weight, but my active lifestyle in the military generally kept me from having a lot of stomach fat. By no means am I "huge", but I would be overweight every time and had to be taped, where I would always pass. What I mean to say is that I know I'm heavier than I look, because I have put on a decent amount of muscle. I'm currently at 230 and wanting to get done to 215. From there I hope to maintain or drop further to 205 if it's not the look I want for myself.

Sorry for the story, lol. I hope to lose 1.5 pounds per week. I generally have 3-4 hundred for breakfast, too much for lunch, 7-9, and around 600 for dinner. I'm currently working a 2nd shift security job so I get a decent amount of walking, paired with weight training in the morning. Today I have 400 left over but I'm feeling hungry, probably because I am up late for work. Is it okay to eat the goal for calories that the app gives you? Or should I strive to have some left over? How much will this hurt or help my progress? I'd appreciate some snack advice.