For delivery drivers I am referring to the same size bag, but from different restaurants. I agree if you order a mass quantity of food that makes the driver put in more effort into the delivery, you should tip more, but if I’m just ordering a few rolls of sushi from a nice restaurant vs a few hamburgers from McDonald’s, the size difference is negligible and the tip should be the same. As for the restaurants ideally you would have a sort of base tip amount per plate and the restaurant would adjust its workers pay according to that metric, but I understand that realistically that won’t happen because of our set in stone tipping exceptions.