It always seemed strange Finnair would use two separate airports for the refuelling in central India because the logistics of changing crews become much more difficult when you use two different places, and you end up with higher costs. For the same reason Boeing 757 charters from Britain to North America always tend to stop at Bangor, Maine regardless of where they are heading on for because that eases these things. You can have people stuck away from home for an awful long time otherwise, sat doing nothing and costing the airline money.
Dubai is even further away from a direct flight route.