Both Janshatabdi and VB are leaving BZA with a gap of 10 mins, i do not see why it should be 15:20 , It could still leave BZA at 13:30 and make early arrival at MAS so people could reach home.
Also a stop at AJJ or TRL necessary for the VB , As this would benefit BZA travelers from AJJ or TRL instead of going to MAS