There are two common point: CBC & Speed permitted!!
The inclusion of P-7 & CBC lead consistent trial to get into final Banker non-requirement with desirable speed !!
Raj, Hybrid, DRNTO all do have CBC Coupling & with less load, P-4 manage 65 KMPH with Raj/DRNTO Rake, which cant be possible for 25 Coach Rake (while it can ascend but with slow speed, which can lead congestion on busy track)!!