I think the poster got confused on the math there, worked it on five pounds,,🤣
Op, the simple fact is this is about the math.
It's Depending on your calorie deficit for the rest of the week v how much of that you use in your treat meal. If you use less than your total calorie deficit, you will lose weight, albeit more slowly. If you use more of it, or all of it, you will lose none. In fact possibly even gain.
So picking carefully and doing the math, is the answer here.
Plus,,,how long do you want to be on a diet for,,,,