And bro agree Darshan Express can have little less occupancy becoz it falls under premium category. But also there are many people who prefer this train the most as compared to your Agra ones.
Imagine the situation if Darshan Express became a common Superfast train with 4 - 6 GS and 11 - SL coaches as like of 22403/04 NDLS - PDY/12449/50 Goa S. Kr or 12483/84 ASR - KCVL? Then what will be situation just think.