it is just like a tea on road will cost you rs 5/ while in 5star will cost you 100/ charges for different category is different.if we build hospital with only deluxe room or only with gen ward it will not serve the purpose. most of time you can have beforehand idea what will be your expenses.
person earning one crore give income tax of rs 30 lakh while person earning upto 3 lakh have no IT liablity while both are using same national resourses more