To analyze the extended stoppages of this train, you need to look that the history and purpose of the train.
The train was originally Bardhaman - Dhanbad Passenger based in BWN CDO, later got extended to GMO and then HTE. With an ICF Rake, this train used to have large amounts of halt duration at ASN, DHN as slack to improve punctuality.
This train was a good connecting train from GMO, BKSC end for Black Diamond connection at DHN. Also previously there was a limited connectivity from/to RNC to the ER line and...
more... this train helped a lot.
After being upgraded to a MEMU rake based off at ASN, this train was sped up substantially in the UP direction. the 30 mins halt at DHN has been done away with, in the down direction, the 90 mins halt at DHN has also been shelved to some extent.
The train mostly acts as two trains clubbed as one nowadays, BWN-DHN/GMO as a separate train and then a separate train GMO onwards, only that they charge express charges now.