Metabolism varies widely among individuals, and there is no clear understanding on the relationship between calorie intake and weight. All the calculators and estimates you find on the internet are based on surface level low-quality estimates that don't (and can't) take into account all of the variances at work. That said I am aware that I'm a bit of an extreme case (always been teased for that) but that's how random variables work, sometimes there are data points outside of the bulk.