I'm quite familiar with the way it works in the US. If it's a birthday dinner or your circle of friends then yes people will likely split it evenly, but if you are a mixed group of people then people will generally pay for what they had. But regardless if its just "60 bucks a head" everyone at the table needs to settle up, and everyone throws in cash in a pile and takes their change out of the pile and then the pile needs to be sorted and counted and sometimes its short etc.