Drawing hidden lines of an object with a hole

Where I pointed with an arrow how come the imaginary lines to show the hole broadens at that point instead of straight down? Is that always the case when it comes to any object that is similar? Thamk you!

Hi there, the middle two lines are representing one of the four holes behind the centre hole so take those out of the equation if you are trying to visualise the product cut exactly in half.
What you have drawn in the bottom left hand side is correct in terms of the cavity and solid areas. Ive drawn on a red line to the original so you can cross reference. I know what you mean though, logically you would think the 'lip' would be where the base of the product starts however sometimes manufacturers try to mould things like that to reduce the amount of material. If they are taking off that blue corner for each object they make that adds up to quite a lot of material saving (and therefore cost saving) overtime. I wouldnt say that all objects are the same as this, it really just depends on how its been moulded. It may have to fit onto something that matches that cavity shape. So it just depends entirely on the object and the GA drawing, there are no hard and fast rules for it