Increasing 12783/84 is not possible as it requires dedicated rake. SCR made 12783/84 to avoid idle time of SC-SHM-SC AC train. SCR might have gone via GNT for couple of reason. 1. Increase occupancy providing stop at GNT for both of the trains, 2. To fee path of KZJ - BZA as it is saturated route. I don't think it would hurt to run via GNT as the total distance is reduced. For that matter 12703/04 doing very well with it schedule as compared with main line trains. 22203/04 totally by-passing BZA may create occupancy issue, that what SCR might have though of. Anyway first SCR should have removed dyn. fare of VSKP Duronto to increase its occupancy.