How Reliable is Precision Nutrition's Calculator?

Link to the calculator I'm looking at

Does anyone have a line on how accurate Precision Nutrition's weight loss calculator is? At face value its pretty in-depth when it comes to input values, but I don't know how much weight (see what I did there) I should put into the results it's giving me. Based on my weight/height/current activity/added activity it says that I should reach my goal weight by my birthday in March - that seems too easy. Maybe I'm just too much in my own head?