Maintenance for minor son

Dear Members, How long does it take to get an interim order for maintenance case u/s 125 CrPC? How does the court arrive at the maintenance amount to be ordered in their interim order?

Generally it takes two or three dates.... 
Only minor son is claiming maintainance ? Mother is not claiming any maintenance?

Generally, it takes two or three dates....

Only minor son is claiming maintenance? Mother is not claiming any maintenance?